Endogenous feline leukemia virus siRNA transcription may interfere with exogenous FeLV infection

Endogenous retroviruses (ERVs) are increasingly recognized for biological impacts on host cell function and susceptibility to infectious agents, particularly in relation to interactions with exogenous retroviral progenitors (XRVs). ERVs can simultaneously promote and restrict XRV infections using mechanisms that are virus- and host-specific. The majority of endogenous-exogenous retroviral interactions have been evaluated in experimental mouse or chicken systems which are limited in their ability to extend findings to naturally infected outbred animals. Feline leukemia virus (FeLV) has a relatively well-characterized endogenous retrovirus with a coexisting virulent exogenous counterpart and is endemic worldwide in domestic cats. We have previously documented an association between endogenous FeLV LTR copy number and abrogated exogenous FeLV in naturally infected cats and experimental infections in tissue culture. Analyses described here examine limited FeLV replication in experimentally infected peripheral blood mononuclear cells which correlates with higher enFeLV transcripts in these cells compared to fibroblasts. We further examine NCBI Sequence Read Archive RNA transcripts to evaluate enFeLV transcripts and RNA interference precursors. We find that lymphoid-derived tissues, which are experimentally less permissive to exogenous FeLV infection, transcribe higher levels of enFeLV under basal conditions. Transcription of enFeLV-LTR segments is significantly greater than other enFeLV genes. We documented transcription of a 21-nt miRNA just 3’ to the enFeLV 5’-LTR in the feline miRNAome of all datasets evaluated (n=27). Our findings point to important biological functions of enFeLV transcription linked to solo LTRs distributed within the domestic cat genome, with potential impacts on domestic cat exogenous FeLV susceptibility and pathogenesis. Importance Endogenous retroviruses (ERVs) are increasingly implicated in host cellular processes and susceptibility to infectious agents, specifically regarding interactions with exogenous retroviral progenitors (XRVs). Exogenous feline leukemia virus (FeLV) and its endogenous counterpart (enFeLV) represent a well characterized, naturally occurring XRV-ERV dyad. We have previously documented an abrogated FeLV infection in both naturally infected cats and experimental fibroblast infections that harbor higher enFeLV proviral loads. Using an in silico approach, we provide evidence of miRNA-transcription that are produced in tissues most important for FeLV infection, replication, and transmission. Our findings point to important biological functions of enFeLV transcription linked to solo-LTRs distributed within the feline genome, with potential impacts on domestic cat exogenous FeLV susceptibility and pathogenesis. This body of work provides additional evidence of RNAi as a mechanism of viral interference and is a demonstration of ERV exaptation by the host to defend against related XRVs.

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Endogenous feline leukemia virus siRNA transcription may interfere with exogenous FeLV infection

10.1101/2021.01.12.426481 ◽

2021 ◽

Author(s):

Elliott S. Chiu ◽

Sue VandeWoude

Keyword(s):

Mononuclear Cells ◽

Cell Function ◽

Leukemia Virus ◽

Endogenous Retroviruses ◽

Domestic Cat ◽

Feline Leukemia Virus ◽

Infectious Agents ◽

Biological Functions ◽

Peripheral Blood Mononuclear ◽

Solo Ltrs

AbstractEndogenous retroviruses (ERVs) are increasingly recognized for biological impacts on host cell function and susceptibility to infectious agents, particularly in relation to interactions with exogenous retroviral progenitors (XRVs). ERVs can simultaneously promote and restrict XRV infections using different mechanisms that are virus- and host-specific. The majority of endogenous-exogenous retroviral interactions have been evaluated in experimental mouse or chicken systems which are limited in their ability to extend findings to naturally infected outbred animals. Feline leukemia virus (FeLV) has a relatively well-characterized endogenous retrovirus with a coexisting virulent exogenous counterpart and is endemic worldwide in domestic cats. We have previously documented an association between endogenous FeLV LTR copy number and abrogated exogenous FeLV in naturally infected cats and experimental infections in tissue culture. Analyses described here examine limited FeLV replication in experimentally infected peripheral blood mononuclear cells. We further examine NCBI Sequence Read Archive RNA transcripts to evaluate enFeLV transcripts and RNA interference precursors. We find that lymphoid-derived tissues, which are experimentally less permissive to exogenous FeLV infection, transcribe higher levels of enFeLV under basal conditions. Transcription of enFeLV-LTR segments is significantly greater than other enFeLV genes. We documented transcription of a 21-nt miRNA just 3′ to the enFeLV 5′-LTR in the feline miRNAome of all datasets evaluated (n=27). Our findings point to important biological functions of enFeLV transcription linked to solo LTRs distributed within the domestic cat genome, with potential impacts on domestic cat exogenous FeLV susceptibility and pathogenesis.ImportanceEndogenous retroviruses (ERVs) are increasingly implicated in host cellular processes and susceptibility to infectious agents, specifically regarding interactions with exogenous retroviral progenitors (XRVs). Exogenous feline leukemia virus (FeLV) and its endogenous counterpart (enFeLV) represent a well characterized, naturally occurring XRV-ERV dyad. We have previously documented an abrogated FeLV infection in both naturally infected cats and experimental fibroblast infections that harbor higher enFeLV proviral loads. Using an in silico approach, we provide evidence of miRNA-transcription that are produced in tissues most important for FeLV infection, replication, and transmission. Our findings point to important biological functions of enFeLV transcription linked to solo-LTRs distributed within the feline genome, with potential impacts on domestic cat exogenous FeLV susceptibility and pathogenesis. This body of work provides additional evidence of RNAi as a mechanism of viral interference and is a demonstration of ERV exaptation by the host to defend against related XRVs.

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Infectious Endogenous Retroviruses in Cats and Emergence of Recombinant Viruses

Journal of Virology ◽

10.1128/jvi.00280-12 ◽

2012 ◽

Vol 86 (16) ◽

pp. 8634-8644 ◽

Cited By ~ 36

Author(s):

Yukari Anai ◽

Haruyo Ochi ◽

Shinya Watanabe ◽

So Nakagawa ◽

Maki Kawamura ◽

...

Keyword(s):

Leukemia Virus ◽

Endogenous Retroviruses ◽

Domestic Cat ◽

Feline Leukemia Virus ◽

Polymorphism Analysis ◽

Domestic Cats ◽

Heterozygous Locus ◽

Recombinant Viruses ◽

Genomic Insertions ◽

Insertional Polymorphism

Endogenous retroviruses (ERVs) comprise a significant percentage of the mammalian genome, and it is poorly understood whether they will remain as inactive genomes or emerge as infectious retroviruses. Although several types of ERVs are present in domestic cats, infectious ERVs have not been demonstrated. Here, we report a previously uncharacterized class of endogenous gammaretroviruses, termed ERV-DCs, that is present and hereditary in the domestic cat genome. We have characterized a subset of ERV-DC proviral clones, which are numbered according to their genomic insertions. One of these, ERV-DC10, located in the q12-q21 region on chromosome C1, is an infectious gammaretrovirus capable of infecting a broad range of cells, including human. Our studies indicate that ERV-DC10 entered the genome of domestic cats in the recent past and appeared to translocate to or reintegrate at a distinct locus as infectious ERV-DC18. Insertional polymorphism analysis revealed that 92 of 244 domestic cats had ERV-DC10 on a homozygous or heterozygous locus. ERV-DC-like sequences were found in primate and rodent genomes, suggesting that these ERVs, and recombinant viruses such as RD-114 and BaEV, originated from an ancestor of ERV-DC. We also found that a novel recombinant virus, feline leukemia virus subgroup D (FeLV-D), was generated by ERV-DCenvtransduction into feline leukemia virus in domestic cats. Our results indicate that ERV-DCs behave as donors and/or acceptors in the generation of infectious, recombinant viruses. The presence of such infectious endogenous retroviruses, which could be harmful or beneficial to the host, may affect veterinary medicine and public health.

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Gammaretrovirus-Specific Antibodies in Free-Ranging and Captive Namibian Cheetahs

Clinical and Vaccine Immunology ◽

10.1128/cvi.00705-14 ◽

2015 ◽

Vol 22 (6) ◽

pp. 611-617 ◽

Cited By ~ 5

Author(s):

Annika Krengel ◽

Valentino Cattori ◽

Marina L. Meli ◽

Bettina Wachter ◽

Jürg Böni ◽

...

Keyword(s):

Reverse Transcriptase ◽

Real Time ◽

Real Time Pcr ◽

Mononuclear Cells ◽

Leukemia Virus ◽

Reverse Transcriptase Activity ◽

Feline Leukemia Virus ◽

Quantitative Real Time Pcr ◽

Peripheral Blood Mononuclear ◽

Free Ranging

ABSTRACTThe cheetah population in Namibia is the largest free-ranging population in the world and a key population for research regarding the health status of this species. We used serological methods and quantitative real-time PCR to test free-ranging and captive Namibian cheetahs for the presence of feline leukemia virus (FeLV), a gammaretrovirus that can be highly aggressive in populations with low genetic diversity, such as cheetahs. We also assessed the presence of antibodies to other gammaretroviruses and the responses to a FeLV vaccine developed for domestic cats. Up to 19% of the free-ranging cheetahs, 27% of the captive nonvaccinated cheetahs, and 86% of the captive vaccinated cheetahs tested positive for FeLV antibodies. FeLV-antibody-positive free-ranging cheetahs also tested positive for Rauscher murine leukemia virus antibodies. Nevertheless, FeLV was not detectable by quantitative real-time PCR and no reverse transcriptase activity was detectable by product-enhanced reverse transcriptase assay in the plasma of cheetahs or the supernatants from cultures of peripheral blood mononuclear cells. The presence of antibodies to gammaretroviruses in clinically healthy specimens may be caused either by infection with a low-pathogenic retrovirus or by the expression of endogenous retroviral sequences. The strong humoral immune responses to FeLV vaccination demonstrate that cheetahs can respond to the vaccine and that vaccination against FeLV infection may be beneficial should FeLV infection ever become a threat, as was seen in Iberian lynx and Florida panthers.

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CERI, CEFX, and CPI: Largely Improved Positive Controls for Testing Antigen-Specific T Cell Function in PBMC Compared to CEF

Cells ◽

10.3390/cells10020248 ◽

2021 ◽

Vol 10 (2) ◽

pp. 248

Author(s):

Alexander A. Lehmann ◽

Pedro A. Reche ◽

Ting Zhang ◽

Maneewan Suwansaard ◽

Paul V. Lehmann

Keyword(s):

T Cell ◽

Mononuclear Cells ◽

Cell Function ◽

Racial Bias ◽

Immune Monitoring ◽

Functional Fitness ◽

Peripheral Blood Mononuclear ◽

Cell Immunity ◽

Antigen Presenting ◽

Positive Controls

Monitoring antigen-specific T cell immunity relies on functional tests that require T cells and antigen presenting cells to be uncompromised. Drawing of blood, its storage and shipment from the clinical site to the test laboratory, and the subsequent isolation, cryopreservation and thawing of peripheral blood mononuclear cells (PBMCs) before the actual test is performed can introduce numerous variables that may jeopardize the results. Therefore, no T cell test is valid without assessing the functional fitness of the PBMC being utilized. This can only be accomplished through the inclusion of positive controls that actually evaluate the performance of the antigen-specific T cell and antigen presenting cell (APC) compartments. For Caucasians, CEF peptides have been commonly used to this extent. Moreover, CEF peptides only measure CD8 cell functionality. We introduce here universal CD8+ T cell positive controls without any racial bias, as well as positive controls for the CD4+ T cell and APC compartments. In summary, we offer new tools and strategies for the assessment of PBMC functional fitness required for reliable T cell immune monitoring.

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Longitudinal high-dimensional analysis identifies biomarkers of response to anti-PD-1 immunotherapy

10.21203/rs.3.rs-863654/v1 ◽

2021 ◽

Author(s):

Run-Ze Li ◽

Xing-Xing Fan ◽

Ze-Bo Jiang ◽

Jumin Huang ◽

Hu-Dan Pan ◽

...

Keyword(s):

Clinical Response ◽

Mononuclear Cells ◽

Cell Function ◽

Immune Cell ◽

Response To Therapy ◽

High Dimensional ◽

Meso Scale Discovery ◽

Peripheral Blood Mononuclear ◽

Poor Outcomes ◽

Nsclc Patients

Abstract The response to immunotherapy could be better predicted by using a wide set of biomarkers, including serum tumor markers; however, robust immune markers associated with efficacy have yet to be validated. In this study, changes in immune cell subsets from NSCLC patients treated with anti-PD1 therapy were longitudinally monitored by high-dimensional cytometry by time of flight (CyTOF) and Meso Scale Discovery (MSD) multi-cytokines kits. The frequencies of circulating CD8+ and CD8+CD101hiTIM3+ (CCT T) subsets were significantly correlated with clinical response and survival. Enrichment of these populations in peripheral blood mononuclear cells (PBMCs) indicated a poor clinical response to ICB therapy. Cell function assays revealed that these subsets were remarkably impaired, which supported the poor outcomes observed. Additionally, longitudinal analysis showed that KLRG1 expression and cytokines were associated with the response to therapy. Overall, our results provide novel potential biomarkers for guiding the management of NSCLC patients eligible to anti-PD-1 therapy, and contribute insights for new therapeutic strategies.

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MicroRNA expression profiling of peripheral blood mononuclear cells associated with syphilis

10.21203/rs.2.9964/v2 ◽

2019 ◽

Author(s):

Tao Huang ◽

Jun Zhang ◽

Wujian Ke ◽

Xiaohui Zhang ◽

Wentao Chen ◽

...

Keyword(s):

Peripheral Blood Mononuclear Cells ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Cell Function ◽

Immune Cell ◽

Treponema Pallidum ◽

Target Sequence ◽

Healthy Individuals ◽

Peripheral Blood Mononuclear ◽

Blood Mononuclear Cells

Abstract Background Treponema pallidum ( T. pallidum ) infection evokes significant immune responses, resulting in tissue damage. The immune mechanism underlying T. pallidum infection is still unclear, although microRNAs (miRNAs) have been shown to influence immune cell function and, consequently, the generation of antibody responses during other microbe infections. However, these mechanisms are unknown for T. pallidum . Methods In this study, we performed a comprehensive analysis of differentially expressed miRNAs in healthy individuals, untreated patients with syphilis, patients in the serofast state, and serologically cured patients. miRNAs were profiled from the peripheral blood of patients obtained at the time of serological diagnosis. Then, both the target sequence analysis of these different miRNAs and pathway analysis were performed to identify important immune and cell signaling pathways. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed for microRNA analysis. Results A total of 89 differentially regulated miRNAs were identified. Following RT-qPCR confirmation, three miRNAs (hsa-miR-195-5p, hsa-miR-223-3p, hsa-miR-589-3p) showed significant differences in the serofast and serologically cured states ( P <0.05). One miRNA (hsa-miR-195-5p) showed significant differences between untreated patients and healthy individuals. Conclusions This is the first study of miRNA expression differences in peripheral blood mononuclear cells (PBMCs) in different stages of T. pallium infection. Our study suggests that the combination of three miRNAs has great potential to serve as a non-invasive biomarker of T. pallium infections, which will facilitate better diagnosis and treatment of T. pallium infections.

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Virological and Parasitological Characterization of Mini-LEWE Minipigs Using Improved Screening Methods and an Overview of Data on Various Minipig Breeds

Microorganisms ◽

10.3390/microorganisms9122617 ◽

2021 ◽

Vol 9 (12) ◽

pp. 2617

Author(s):

Sabrina Halecker ◽

Julia Metzger ◽

Christina Strube ◽

Ludwig Krabben ◽

Benedikt Kaufer ◽

...

Keyword(s):

Mononuclear Cells ◽

Massachusetts General Hospital ◽

Hepatitis E ◽

Human Cells ◽

Gastrointestinal Parasites ◽

Endogenous Retroviruses ◽

Detection Methods ◽

Screening Methods ◽

Rt Pcr ◽

Peripheral Blood Mononuclear

Minipigs play an important role in biomedical research and have also been used as donor animals in xenotransplantation. To serve as a donor in xenotransplantation, the animals must be free of potential zoonotic viruses, bacteria and parasites. Porcine endogenous retroviruses (PERVs) are integrated in the genome of all pigs and cannot be eliminated as most of the other pig viruses can. PERV-A and PERV-B infect human cells in cell culture and are integrated in all pigs, whereas PERV-C infects only pig cells and it is found in many, but not all pigs. Minipigs are known for a high prevalence of recombinant PERV-A/C viruses able to infect human cells (Denner and Schuurman, Viruses, 2021;13:1869). Here, Mini-LEWE minipigs are screened for the first time for pig viruses including PERV. Peripheral blood mononuclear cells (PBMCs) from 10 animals were screened using PCR-based methods (PCR, RT-PCR, and real-time PCR). In comparison with our previous screening assays, numerous improvements were introduced, e.g., the usage of gene blocks as a PCR standard and foreign RNA to control reverse transcription in RT-PCR. Using these improved detection methods, Mini-LEWE pigs were found to be negative for porcine cytomegalovirus (PCMV), porcine lymphotropic herpesviruses (PLHV-1, -2 and -3), porcine circoviruses (PCV1, 2, 3 and 4), porcine parvovirus (PPV) and hepatitis E virus (HEV). All animals carried PERV-A, PERV-B and PERV-C in their genome. PERV-A/C was not found. In contrast to all other minipig breeds (Göttingen minipigs, Aachen minipigs, Yucatan micropig, Massachusetts General Hospital miniature pigs), Mini-LEWE minipigs have less viruses and no PERV-A/C. Parasitological screening showed that none of the Mini-LEWE minipigs harbored ecto- and gastrointestinal parasites, but at least one animal tested positive for anti-Toxoplasma gondii antibodies.

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Ancestral Mutations Acquired in Refrex-1, a Restriction Factor against Feline Retroviruses, during its Cooption and Domestication

Journal of Virology ◽

10.1128/jvi.01904-15 ◽

2015 ◽

Vol 90 (3) ◽

pp. 1470-1485 ◽

Cited By ~ 7

Author(s):

Jumpei Ito ◽

Takuya Baba ◽

Junna Kawasaki ◽

Kazuo Nishigaki

Keyword(s):

Field Model ◽

Leukemia Virus ◽

Endogenous Retroviruses ◽

Chimeric Virus ◽

Feline Leukemia Virus ◽

Domestic Cats ◽

Terminal Domain ◽

Viral Particles ◽

Triangular Relationships ◽

Retroviral Infections

ABSTRACTEndogenous retroviruses (ERVs) are remnants of ancestral retroviral infections of germ cells. Retroviral endogenization is an adaptation process for the host genome, and ERVs are gradually attenuated or inactivated by mutation. However, some ERVs that have been “domesticated” by their hosts eventually gain physiological functions, such as placentation or viral resistance. We previously reported the discovery of Refrex-1, a soluble antiretroviral factor in domestic cats that specifically inhibits infection by feline leukemia virus subgroup D (FeLV-D), a chimeric virus of FeLV, and a feline ERV, ERV-DC. Refrex-1 is a truncated envelope protein (Env) encoded by both ERV-DC7 and ERV-DC16 proviral loci. Here, we reconstituted ancestral and functional Env from ERV-DC7 and ERV-DC16 envelope genes (env) by inducing reverse mutations. Unexpectedly, ERV-DC7 and ERV-DC16 full-length Env (ERV-DC7 fl and ERV-DC16 fl), reconstructed by removing stop codons, did not produce infectious viral particles. ERV-DC7 fl and ERV-DC16 fl were highly expressed in cells but were not cleaved into surface subunits (SU) and transmembrane subunits, nor were they incorporated into virions. G407R/N427I-A429T and Y431D substitutions within the SU C-terminal domain of ERV-DC7 fl and ERV-DC16 fl, respectively, caused these dysfunctions. The residues glycine 407 and tyrosine 431 are relatively conserved among infectious gammaretroviruses, and their substitution causes the same dysfunctions as the tested retroviruses. Our results reveal that specific mutations within the SU C-terminal domain suppressed Env cleavage and incorporation into virions and indicate that these mutations contributed to the domestication of Refrex-1 through multistep events that occurred in the postintegration period.IMPORTANCEDomestic cats are colonized with various exogenous retroviruses (exRVs), such as feline leukemia virus (FeLV), and their genomes contain numerous ERVs, some of which are replication-competent proviruses. The feline hosts, exRVs, and ERVs have complicated genetic interactions and provide an interesting field model for triangular relationships: recombination between FeLV and ERV-DC, which is a feline ERV, generated FeLV-D, a chimeric virus, and FeLV-D is restricted by Refrex-1, an antiretroviral factor corresponding to truncated Env of ERV-DC7 and ERV-DC16. Here, we reconstructed ancestral, functional Env from ERV-DC7 and ERV-DC16envby inducing reverse mutations to elucidate how Refrex-1 was generated from its ancestor. Our results reveal that they were repeatedly inactivated by mutations preventing Env maturation. Our results provide insights into how ERVs were “domesticated” by their hosts and identify the mutations that mediated these evolutions. Notably, experiments that restore inactivated ERVs might uncover previously unrecognized features or properties of retroviruses.

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Clinical significance of insulin peptide-specific interferon-γ-related immune responses in ketosis-prone type 2 diabetes

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgab912 ◽

2021 ◽

Author(s):

Atsushi Satomura ◽

Yoichi Oikawa ◽

Akifumi Haisa ◽

Seiya Suzuki ◽

Shunpei Nakanishi ◽

...

Keyword(s):

Type 2 Diabetes ◽

Immune Responses ◽

Elispot Assay ◽

Mononuclear Cells ◽

Cell Function ◽

Β Cell ◽

Peripheral Blood Mononuclear ◽

Β Cell Function ◽

Ifn Γ

Abstract Context Unprovoked A−β+ ketosis-prone type 2 diabetes (KPD) is characterized by the sudden onset of diabetic ketosis/ketoacidosis (DK/DKA) without precipitating factors, negative anti-islet autoantibodies (“A−”), and preservation of β-cell function (“β+”) after recovery from DKA. Although this phenotype often appears with acute hyperglycemia and DK/DKA just like acute-onset type 1 diabetes (AT1D), the involvement of anti-islet immune responses remains unknown. Objective We sought to clarify the immunological role of insulin-associated molecules in unprovoked A−β+ KPD. Methods In this cross-sectional study, blood samples from 75 participants (42 with AT1D and 33 with KPD) were evaluated for interferon (IFN)-γ-secreting peripheral blood mononuclear cells (PBMCs) reactive to four insulin B-chain amino acid 9–23-related peptides (B:9–23rPep) using an enzyme-linked immunospot (ELISpot) assay. Results Overall, 36.4% (12/33) of KPD participants showed positive IFN-γ ELISpot assay results; the positivity rate in KPD was similar to that in AT1D (38.1%; 16/42) and significantly higher than the previously reported rate in type 2 diabetes (8%; 2/25; P < 0.0167). Moreover, B:9–23rPep-specific IFN-γ-producing PBMC frequency was negatively correlated with age and ad lib serum C-peptide levels in all KPD participants and positively correlated with HbA1c level in KPD participants with positive IFN-γ ELISpot results. Conclusions These findings suggest the involvement of B:9–23rPep-specific IFN-γ-related immunoreactivity in the pathophysiology of some unprovoked A−β+ KPD. Moreover, increased immunoreactivity may reflect transiently decreased β-cell function and increased disease activity at the onset of DK/DKA, thereby playing a key role in DK/DKA development in this KPD phenotype.

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BTK Inhibitors, Irrespective of ITK Inhibition, Increase Efficacy of a CD19/CD3 Bispecific Antibody in CLL

Blood ◽

10.1182/blood.2020009686 ◽

2021 ◽

Author(s):

Maissa Mhibik ◽

Erika M. Gaglione ◽

David Eik ◽

Ellen K Kendall ◽

Amy Blackburn ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cytotoxic Activity ◽

Kinase Inhibitors ◽

Bispecific Antibody ◽

Mononuclear Cells ◽

Cell Function ◽

Lymphocytic Leukemia ◽

Peripheral Blood Mononuclear

Bruton Tyrosine Kinase inhibitors (BTKis) are a preferred treatment for patients with chronic lymphocytic leukemia (CLL). Indefinite therapy with BTKis, while effective, presents clinical challenges. Combination therapy can deepen responses, shorten treatment duration, and possibly prevent or overcome drug resistance. We previously reported on a CD19/CD3 bispecific antibody (bsAb) that recruits autologous T cell cytotoxicity against CLL cells in vitro. Compared to observations with samples from treatment-naïve patients, T cells from patients being treated with ibrutinib expanded more rapidly and exerted superior cytotoxic activity in response to the bsAb. In addition to BTK, ibrutinib also inhibits IL2 inducible T cell Kinase (ITK). In contrast, acalabrutinib, does not inhibit ITK. Whether ITK inhibition contributes to the observed immune effects is unknown. To better understand how BTKis modulate T-cell function and cytotoxic activity, we cultured peripheral blood mononuclear cells (PBMCs) from BTKi-naive, and ibrutinib- or acalabrutinib-treated CLL patients with CD19/CD3 bsAb in vitro. T-cell expansion, activation, differentiation, and cytotoxicity were increased in PBMCs from patients on treatment with either BTKi compared to that observed for BKTi-naïve patients. BTKi therapy transcriptionally downregulated immunosuppressive effectors expressed by CLL cells, including CTLA-4 and CD200. CTLA-4 blockade with ipilimumab in vitro increased the cytotoxic activity of the bsAb in BTKi-naïve but not BTKi-treated PBMCS. Taken together, BTKis enhance bsAb induced cytotoxicity by relieving T cells of immunosuppressive restraints imposed by CLL cells. The benefit of combining bsAb immunotherapy with BTKis needs to be confirmed in clinical trials.

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