Taming C-terminal peptides of Staphylococcus aureus leukotoxin M for B-cell response: Implication in improved subclinical bovine mastitis diagnosis and protective efficacy in vitro

AbstractPrevious studies have suggested that murine T cells are tolerant to epitopes derived from germ line variable regions of immunoglobulin (Ig) heavy (VH) or light chains. This has lead to the prediction that germ line VH-region epitopes found in neoplastic B cells cannot be used to provoke an antitumor immune response. To test these assumptions and address the question of how such a vaccine may alter the normal B-cell response, an antibody-forming B-cell hybridoma (1H6) expressing a conserved germ line VH gene with specificity for dextran was generated and used as a tumor model. Using algorithms for predicting major histocompatibility complex (MHC) binding, potential MHC class I and II binding peptides were identified within the 1H6 VH region, synthesized, and tested for MHC binding and immunogenicity. We show that germ line VH peptides, when presented by dendritic cells, are immunogenic in vitro and provoke a tumor-specific protective immune response in vivo. We conclude that (1) it is possible to induce a T-cell response to germ line VH peptides; (2) such peptides can be used to generate a B-cell tumor-specific vaccine; and (3) a vaccine targeting VH peptides expressed by the dominant dextran-specific B-cell clonotype had no effect upon the magnitude of the normal B-cell response to dextran.

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PPE Antigen Rv2430c of Mycobacterium tuberculosis Induces a Strong B-Cell Response

Infection and Immunity ◽

10.1128/iai.71.11.6338-6343.2003 ◽

2003 ◽

Vol 71 (11) ◽

pp. 6338-6343 ◽

Cited By ~ 101

Author(s):

Rakesh Kumar Choudhary ◽

Sangita Mukhopadhyay ◽

Prachee Chakhaiyar ◽

Naresh Sharma ◽

K. J. R. Murthy ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

B Cell ◽

Cell Response ◽

Mrna Level ◽

Immunoglobulin M ◽

Enzyme Linked Immunosorbent Assay ◽

Healthy Controls ◽

Protein Families ◽

B Cell Response

ABSTRACT The variation in sequence and length in the C-terminal region among members of the unique PE (Pro-Glu) and PPE (Pro-Pro-Glu) protein families of Mycobacterium tuberculosis is a likely source of antigenic variation, giving rise to the speculation that these protein families could be immunologically important. Based on in silico analysis, we selected a hypothetical open reading frame (ORF) encoding a protein belonging to the PPE family and having epitopes with predictably higher antigenic indexes. Reverse transcriptase PCR using total RNA extracted from in vitro-cultured M. tuberculosis H37Rv generated an mRNA product corresponding to this gene, indicating the expression of this ORF (Rv2430c) at the mRNA level. Recombinant protein expressed in Escherichia coli was used to screen the sera of M. tuberculosis-infected patients, as well as those of clinically healthy controls (n = 10), by enzyme-linked immunosorbent assay. The panel of patient sera comprised sera from fresh infection cases (category 1; n = 32), patients with relapsed tuberculosis (category 2; n = 30), and extrapulmonary cases (category 3; n = 30). Category 2 and 3 sera had strong antibody responses to the PPE antigen, equal to or higher than those to other well-known antigens, such as Hsp10 or purified protein derivative (PPD). However, a higher percentage of patients belonging to category 1, as opposed to clinically healthy controls, showed stronger antibody response against the PPE protein when probed with anti-immunoglobulin M (IgM) (71 versus 37.5%) or anti-IgG (62.5 versus 28.12%). Our results reveal that this PPE ORF induces a strong B-cell response compared to that generated by M. tuberculosis Hsp10 or PPD, pointing to the immunodominant nature of the protein.

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Rapid isolation and immune profiling of SARS-CoV-2 specific memory B cell in convalescent COVID-19 patients via LIBRA-seq

Signal Transduction and Targeted Therapy ◽

10.1038/s41392-021-00610-7 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Bing He ◽

Shuning Liu ◽

Yuanyuan Wang ◽

Mengxin Xu ◽

Wei Cai ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Single Cell ◽

Cell Response ◽

Critical Role ◽

Antigen Specificity ◽

Memory B Cell ◽

Specific Memory ◽

B Cell Response

AbstractB cell response plays a critical role against SARS-CoV-2 infection. However, little is known about the diversity and frequency of the paired SARS-CoV-2 antigen-specific BCR repertoire after SARS-CoV-2 infection. Here, we performed single-cell RNA sequencing and VDJ sequencing using the memory and plasma B cells isolated from five convalescent COVID-19 patients, and analyzed the spectrum and transcriptional heterogeneity of antibody immune responses. Via linking BCR to antigen specificity through sequencing (LIBRA-seq), we identified a distinct activated memory B cell subgroup (CD11chighCD95high) had a higher proportion of SARS-CoV-2 antigen-labeled cells compared with memory B cells. Our results revealed the diversity of paired BCR repertoire and the non-stochastic pairing of SARS-CoV-2 antigen-specific immunoglobulin heavy and light chains after SARS-CoV-2 infection. The public antibody clonotypes were shared by distinct convalescent individuals. Moreover, several antibodies isolated by LIBRA-seq showed high binding affinity against SARS-CoV-2 receptor-binding domain (RBD) or nucleoprotein (NP) via ELISA assay. Two RBD-reactive antibodies C14646P3S and C2767P3S isolated by LIBRA-seq exhibited high neutralizing activities against both pseudotyped and authentic SARS-CoV-2 viruses in vitro. Our study provides fundamental insights into B cell response following SARS-CoV-2 infection at the single-cell level.

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The amplifier role of T cells in the human in vitro B cell response to type 4 pneumococcal polysaccharide

Immunology Letters ◽

10.1016/0165-2478(92)90060-2 ◽

1992 ◽

Vol 32 (3) ◽

pp. 265-272 ◽

Cited By ~ 20

Author(s):

Arjan W. Griffioen ◽

Elly A.H. Toebes ◽

Ger T. Rijkers ◽

Frans H.J. Claas ◽

Gert Datema ◽

...

Keyword(s):

T Cells ◽

B Cell ◽

Cell Response ◽

B Cell Response

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Follicular Helper T (TFH) Cell Targeting by TLR8 Signaling For Improving HBsAg-Specific B Cell Response In Chronic Hepatitis B Patients

Frontiers in Immunology ◽

10.3389/fimmu.2021.735913 ◽

2021 ◽

Vol 12 ◽

Author(s):

Natarajan Ayithan ◽

Lydia Tang ◽

Susanna K. Tan ◽

Diana Chen ◽

Jeffrey J. Wallin ◽

...

Keyword(s):

Chronic Hepatitis ◽

B Cells ◽

Hepatitis B ◽

B Cell ◽

Cell Response ◽

Functional Cure ◽

Cell Responses ◽

Follicular Helper ◽

B Cell Response

Identifying signaling pathways that induce B cell response can aid functional cure strategies for chronic hepatitis B infection (CHB). TLR8 activation with ssRNA was shown to enhance follicular helper T cell (TFH) function leading to improved B cell responses in vitro. We investigated whether this mechanism can rescue an exhausted immune response in CHB infection. Effect of TLR8 agonism on supporting cytokines and TFH and B cells were evaluated using ex vivo and in vitro assays. The ability of an oral TLR8 agonist to promote TFH and B cell response was tested in samples from phase 1b clinical trial. TLR8 agonism induced TFH polarizing cytokine IL-12 in monocytes. Treatment of peripheral blood mononuclear cells (PBMCs) from CHB patients with TLR8 agonists induced cytokine IL-21 by TFH cells with enhanced IL-21+BCL-6+ and ICOS+BCL-6+ co-expression. Mechanistically, incubation of isolated naïve CD4+ T cells with TLR8 triggered monocytes resulted in their differentiation into IL-21+ICOS+BCL-6+ TFH in an IL-12 dependent manner. Furthermore, co-culture of these IL-21 producing TFH with autologous naïve B cells led to enhanced memory (CD19+CD27+) and plasma B cell generation (CD19+CD27++CD38+) and IgG production. Importantly, in TFH from CHB patients treated with an oral TLR8 agonist, HBsAg-specific BCL-6, ICOS, IL-21 and CD40L expression and rescue of defective activation induced marker (AIM) response along with partial restoration of HBsAg-specific B cell ELISPOT response was evident. TLR8 agonism can thus enhance HBV-specific B cell responses in CHB patients by improving monocyte-mediated TFH function and may play a role in achieving HBV functional cure.

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