scholarly journals Interferon-γ-Producing CD4+ T Cells Drive Monocyte Activation in the Bone Marrow During Experimental Leishmania donovani Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Audrey Romano ◽  
Najmeeyah Brown ◽  
Helen Ashwin ◽  
Johannes S. P. Doehl ◽  
Jonathan Hamp ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Leishmania Donovani ◽  
Parasitic Infection ◽  
Parasite Load ◽  
Interferon Γ ◽  
Monocyte Activation ◽  
Inflammatory Monocytes ◽  
Transient Activation ◽  
Bone Marrow Chimeras

Ly6Chi inflammatory monocytes develop in the bone marrow and migrate to the site of infection during inflammation. Upon recruitment, Ly6Chi monocytes can differentiate into dendritic cells or macrophages. According to the tissue environment they can also acquire different functions. Several studies have described pre-activation of Ly6Chi monocytes in the bone marrow during parasitic infection, but whether this process occurs during experimental visceral leishmaniasis and, if so, the mechanisms contributing to their activation are yet to be established. In wild type C57BL/6 (B6) mice infected with Leishmania donovani, the number of bone marrow Ly6Chi monocytes increased over time. Ly6Chi monocytes displayed a highly activated phenotype from 28 days to 5 months post infection (p.i), with >90% expressing MHCII and >20% expressing iNOS. In comparison, in B6.Rag2-/- mice <10% of bone marrow monocytes were MHCII+ at day 28 p.i., an activation deficiency that was reversed by adoptive transfer of CD4+ T cells. Depletion of CD4+ T cells in B6 mice and the use of mixed bone marrow chimeras further indicated that monocyte activation was driven by IFNγ produced by CD4+ T cells. In B6.Il10-/- mice, L. donovani infection induced a faster but transient activation of bone marrow monocytes, which correlated with the magnitude of CD4+ T cell production of IFNγ and resolution of the infection. Under all of the above conditions, monocyte activation was associated with greater control of parasite load in the bone marrow. Through reinfection studies in B6.Il10-/- mice and drug (AmBisome®) treatment of B6 mice, we also show the dependence of monocyte activation on parasite load. In summary, these data demonstrate that during L. donovani infection, Ly6Chi monocytes are primed in the bone marrow in a process driven by CD4+ T cells and whereby IFNγ promotes and IL-10 limits monocyte activation and that the presence of parasites/parasite antigen plays a crucial role in maintaining bone marrow monocyte activation.

scholarly journals Interferon-γ-producing CD4+ T cells drive monocyte activation in the bone marrow during experimental Leishmania donovani infection.

2021 ◽  
Author(s):  
Audrey Romano ◽  
Najmeeyah Brown ◽  
Helen Ashwin ◽  
Johannes S.P. Doehl ◽  
Jonathan Hamp ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cd4 T Cells ◽  
Leishmania Donovani ◽  
Parasitic Infection ◽  
Parasite Load ◽  
Interferon Γ ◽  
Monocyte Activation ◽  
Inflammatory Monocytes ◽  
Transient Activation

Ly6Chi inflammatory monocytes develop in the bone marrow and migrate to the site of infection during inflammation. Upon recruitment, Ly6Chi monocytes can differentiate into dendritic cells or macrophages. According to the tissue environment they can also acquire different functions. Several studies have described pre-activation of Ly6Chi monocytes in the bone marrow during parasitic infection, but whether this process occurs during experimental visceral leishmaniasis and, if so, the mechanisms contributing to their activation are yet to be established. In wild type C57BL/6 (B6) mice infected with Leishmania donovani, the number of bone marrow Ly6Chi monocytes increased over time. Ly6Chi monocytes displayed a highly activated phenotype from 28 days to 5 months post infection (p.i), with >90% expressing MHCII and >20% expressing iNOS. In comparison, in B6.Rag2-/- mice <10% of bone marrow monocytes were MHCII+ at day 28 p.i., an activation deficiency that was reversed by adoptive transfer of CD4+ T cells. Depletion of CD4+ T cells in B6 mice and the use of mixed bone marrow chimeras further indicated that monocyte activation was driven by IFNγproduced by CD4+ T cells. In B6.Il10-/- mice, L. donovani infection induced a faster but transient activation of bone marrow monocytes, which correlated with the magnitude of CD4+ T cell production of IFNγ and resolution of the infection. Under all of the above conditions, monocyte activation was associated with greater control of parasite load in the bone marrow. Through reinfection studies in B6.Il10-/- mice and drug (AmBisome) treatment of B6 mice, we also show the dependence of monocyte activation on parasite load. In summary, these data demonstrate that during L. donovani infection, Ly6Chi monocytes are primed in the bone marrow in a process driven by CD4+ T cells and whereby IFN-γ promotes and IL-10 limits monocyte activation and that the presence of parasites/parasite antigen plays a crucial role in maintaining bone marrow monocyte activation.

scholarly journals INDUCTION OF A HEMOLYSIN RESPONSE IN VITRO

1971 ◽  
Vol 133 (6) ◽  
pp. 1325-1333 ◽  
Author(s):  
Klaus-Ulrich Hartmann
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
B Cells ◽  
Close Contact ◽  
Precursor Cells ◽  
Spleen Cells ◽  
High Concentrations ◽  
Thymus Cells ◽  
Bone Marrow Chimeras

Spleen cells of bone marrow chimeras (B cells) and of irradiated mice injected with thymus cells and heterologous erythrocytes (educated T cells) were mixed and cultured together (17). The number of PFC developing in these cultures was dependent both on the concentration of the B cells and of the educated T cells. In excess of T cells the number of developing PFC is linearly dependent on the number of B cells. At high concentrations of T cells more PFC developed; the increase in the number of PFC was greatest between the 3rd and 4th day of culture. Increased numbers of educated T cells also assisted the development of PFC directed against the erythrocytes. It is concluded that the T cells not only play a role during the triggering of the precursor cells but also during the time of proliferation of the B cells; close contact between B and T cells seems to be needed to allow the positive activity of the T cells.

scholarly journals The role of the Th1 transcription factor T-bet in a mouse model of immune-mediated bone-marrow failure

Blood ◽  
2010 ◽  
Vol 115 (3) ◽  
pp. 541-548 ◽  
Author(s):  
Yong Tang ◽  
Marie J. Desierto ◽  
Jichun Chen ◽  
Neal S. Young
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Transcription Factor ◽  
Transforming Growth Factor ◽  
Bone Marrow Failure ◽  
Critical Role ◽  
Interferon Γ ◽  
Interleukin 17 ◽  
Immune Mediated

Abstract The transcription factor T-bet is a key regulator of type 1 immune responses. We examined the role of T-bet in an animal model of immune-mediated bone marrow (BM) failure using mice carrying a germline T-bet gene deletion (T-bet−/−). In comparison with normal C57BL6 (B6) control mice, T-bet−/− mice had normal cellular composition in lymphohematopoietic tissues, but T-bet−/− lymphocytes were functionally defective. Infusion of 5 × 106 T-bet−/− lymph node (LN) cells into sublethally irradiated, major histocompatibility complex–mismatched CByB6F1 (F1) recipients failed to induce the severe marrow hypoplasia and fatal pancytopenia that is produced by injection of similar numbers of B6 LN cells. Increasing T-bet−/− LN-cell dose to 10 to 23 × 106 per recipient led to only mild hematopoietic deficiency. Recipients of T-bet−/− LN cells had no expansion in T cells or interferon-γ–producing T cells but showed a significant increase in Lin−Sca1+CD117+CD34− BM cells. Plasma transforming growth factor-β and interleukin-17 concentrations were increased in T-bet−/− LN-cell recipients, possibly a compensatory up-regulation of the Th17 immune response. Continuous infusion of interferon-γ resulted in hematopoietic suppression but did not cause T-bet−/− LN-cell expansion or BM destruction. Our data provided fresh evidence demonstrating a critical role of T-bet in immune-mediated BM failure.

scholarly journals Interleukin 2 is an Upstream Regulator of CD4+ T Cells From Visceral Leishmaniasis Patients With Therapeutic Potential

2019 ◽  
Vol 220 (1) ◽  
pp. 163-173 ◽  
Author(s):  
Shashi Bhushan Chauhan ◽  
Rebecca Faleiro ◽  
Rajiv Kumar ◽  
Susanna Ng ◽  
Bhawana Singh ◽  
...  
Keyword(s):  
T Cells ◽  
Visceral Leishmaniasis ◽  
Cd4 T Cells ◽  
Leishmania Donovani ◽  
Therapeutic Potential ◽  
Interleukin 2 ◽  
Interferon Γ ◽  
Immune Functions ◽  
T Regulatory Cell ◽  
Upstream Regulator

Abstract Control of visceral leishmaniasis (VL) caused by Leishmania donovani requires interferon-γ production by CD4+ T cells. In VL patients, antiparasitic CD4+ T-cell responses are ineffective for unknown reasons. In this study, we measured the expression of genes associated with various immune functions in these cells from VL patients and compared them to CD4+ T cells from the same patients after drug treatment and from endemic controls. We found reduced GATA3, RORC, and FOXP3 gene expression in CD4+ T cells of VL patients, associated with reduced Th2, Th17, and FOXP3+CD4+ T regulatory cell frequencies in VL patient blood. Interleukin 2 (IL-2) was an important upstream regulator of CD4+ T cells from VL patients, and functional studies demonstrated the therapeutic potential of IL-2 for improving antiparasitic immunity. Together, these results provide new insights into the characteristics of CD4+ T cells from VL patients that can be used to improve antiparasitic immune responses.

scholarly journals Regulation of Microglia by CD4+ and CD8+ T Cells: Selective Analysis in CD45-congenic Normal and Toxoplasma gondii-infected Bone Marrow Chimeras

2006 ◽  
Vol 11 (1) ◽  
pp. 44-55 ◽  
Author(s):  
Dirk Schlüter ◽  
Timothy Meyer ◽  
Andreas Strack ◽  
Sabine Reiter ◽  
Marianne Kretschmar ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Toxoplasma Gondii ◽  
Cd8 T Cells ◽  
Bone Marrow Chimeras ◽  
Selective Analysis

scholarly journals Restricted helper function of F1 leads to parent bone marrow chimeras controlled by K-end of H-2 complex.

1978 ◽  
Vol 147 (6) ◽  
pp. 1838-1842 ◽  
Author(s):  
J Sprent
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
T Cells ◽  
B Cells ◽  
Parental Strain ◽  
T Helper ◽  
F1 Hybrid ◽  
Active Suppression ◽  
Helper Function ◽  
Bone Marrow Chimeras

F1 leads to parent bone marrow chimeras were prepared by transferring F1 hybrid marrow cells into heavily irradiated parental strain mice. When unprimed, donor-derived F1 T cells from the chimeras were activated to sheep erythrocytes (SRC) for 5 days in irradiated normal F1 mice, high IgM and IgG anti-SRC responses were observed with F1 B cells, and with B cells H-2-compatible with the strain in which the T cells were raised from stem cells. Significantly, however, responses with B cells of the opposite parental strain were either absent or very low. The restriction in T-helper function mapped to the K-end of the H-2 complex and could not be attributed to active suppression.

scholarly journals Cytotoxic T lymphocyte responses in allogeneic radiation bone marrow chimeras. The chimeric host strictly dictates the self-repertoire of Ia-restricted T cells but not H-2K/D-restricted T cells.

1982 ◽  
Vol 156 (6) ◽  
pp. 1650-1664 ◽  
Author(s):  
S M Bradley ◽  
A M Kruisbeek ◽  
A Singer
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cell Interaction ◽  
The Self ◽  
Cellular Interactions ◽  
Stringent Requirement ◽  
Th Cells ◽  
Donor Type ◽  
Bone Marrow Chimeras ◽  
Ctl Responses

The present report has used fully H-2 allogeneic radiation bone marrow chimeras to assess the role of host restriction elements in determining the self-specificity of Ia- and H-2K/D-restricted T cells that participate in the generation of trinitrophenyl (TNP)-specific cytotoxic T lymphocytes (CTL). It was demonstrated that there exists a stringent requirement for the recognition of host thymic-type Ia determinants, but there exists only a preference for host thymic-type H-2K/D determinants. Indeed, once the stringent requirement for recognition of host Ia determinants was fulfilled, anti-TNP CTL were generated in response to TNP-modified stimulators that expressed either donor-type or host-type H-2K/D determinants. The CTL that were generated in response to TNP-modified donor-type stimulators were shown to be specific for TNP and restricted to the non-thymic H-2K/D determinants of the chimeric donor. Thus, these results demonstrate in a single immune response that the thymic hypothesis accurately predicts the self-specificity expressed by Ia-restricted T cells, but does not fully account for the self-specificity expressed by H-2K/D-restricted T cells. These results are consistent with the concept that H-2K/D-restricted T cells, but not Ia-restricted T cells, can differentiate into functional competence either intrathymically or extra-thymically. The present results are also informative for understanding the cellular interactions that are required for the generation of antigen-specific CTL responses. The Ia-restricted T cells that are required for the generation of H-2K/D-restricted anti-TNP CTL were shown to be helper T (TH) cells since (a) like TH cells functioning in antibody responses, they were specific for Ia determinants expressed by accessory cells, and (b) their function could be replaced by either TNP-primed, irradiated TH cells or by nonspecific soluble helper factors. It was also shown that the T-T cell interaction between Ia-restricted TH cells and H-2K/D-restricted precursor CTL (pCTL) is not Ia restricted. Rather, the results demonstrate that the generation of anti-TNP CTL responses involve two parallel sets of major histocompatibility complex-restricted cell interactions, an Ia-restricted TH-accessory cell interaction required for TH cell activation, and an H-2K/D-restricted pCTL-stimulator cell interaction required for pCTL stimulation. The interaction between activated TH cells and stimulated pCTL is mediated, at least in part, by nonspecific soluble helper factors.

scholarly journals The immune response of allophenic mice to 2,4-dinitrophenyl (DNP)-bovine gamma globulin. I. Allotype analysis of anti-DNP antibody

1978 ◽  
Vol 147 (6) ◽  
pp. 1849-1853 ◽  
Author(s):  
CM Warner ◽  
TJ Berntson ◽  
L Eakley ◽  
JL McIvor ◽  
RC Newton
Keyword(s):  
Bone Marrow ◽  
Immune Response ◽  
T Cells ◽  
B Cells ◽  
Glutamic Acid ◽  
Gamma Globulin ◽  
High Responder ◽  
Gene Control ◽  
Low Responder ◽  
Bone Marrow Chimeras

The question of whether or not lymphoid cells can cooperate across a histocompatibility difference barrier has been studied in several laboratories. Using an adoptive transfer system, Katz et al. (1) first showed that T cells from (low responder × high responder) F(1) mice, primed to the terpolymer L-glutamic acid, L-lysine, L-tyrosine (GLT), could collaborate with 2,4-dinitrophenyl (DNP)-primed B cells from a high responder, but not a low responder strain, in response to DNP-GLT. The response to GLT is under H- 2-1inked Ir gene control. In contrast, studies with mouse bone marrow chimeras have shown that T cells can interact with H-2-histoincompatible B cells in response to antigens not under Ir gene control (2-4). Another type of chimera, the allophenic mouse, has been used to study possible histoincompatible cell interactions to a number of antigens, including DNP-L- glutamic acid, L-lysine, L-alanine; L-glutamic acid, L-alanine, L-tyrosine; L-glutamic acid, L-lysine, L-phenylalanine; and poly-L (Tyr, Glu)-poly D,L- Ala-poly-L-Lys[T,G)-A-L] (5-9). The response to each of these antigens is under H-2-1inked Ir gene control. It was initially reported (8, 9) that in allophenic mice containing both high and low responder cells, the antibody to (T,G)-A-L was of both the high and low responder allotype. This was interpreted to mean that high responder T cells had cooperated with low responder B cells across a histocompatibility difference barrier in the environment of the allophenic mice. However, Press and McDevitt (10) have recently reported that additional and more accurate analyses of these allophenic mouse sera failed to detect any anti-(T,G)-A-L antibody of the low responder allotype. Moreover, in an experiment using bone marrow chimeras, there was no low responder allotype antibody produced in response to (T,G)-A- L(10). The present study was undertaken to test the immune response of allophonic mice to an antigen, DNP-bovine gamma globulin (DNP(56)BGG), known to be controlled by genes both inside and outside the H-2 complex (11, 12).(1) When high and low responder cells to DNP(56)BGG are present in allophenic mice, only antibody of the high responder allotype is produced. The results suggest that cell cooperation in allophenic mice cannot occur across a histocompatibility difference barrier in response to an antigen whose genetic control is at least partially within the H-2 complex.

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