Epitope specificity of the T cell proliferative response to lysozyme: proliferative T cells react predominantly to different determinants from those recognized by B cells

In 99 adults infected with human immunodeficiency virus type 1 (HIV-1) who received highly active antiretroviral therapy (HAART) (including 2 nucleoside analogues and 1 or 2 protease inhibitors) for 1 year, CD4+ and CD8+ T cells (including memory and naive subsets) increased similarly among patients with sustained plasma viral load decrease, transient decrease, or no decrease. A linear correlation was observed between the decrease in serum β2-microglobulin concentration (an independent surrogate marker of HIV disease) and the increase in peripheral blood T-cells (CD4+ and CD8+) counts. In vitro, HIV protease inhibitors indinavir and saquinavir (but not nucleoside analogues) enhanced the survival of patients' peripheral blood T cells at doses that are at least 30-fold lower than those required for achieving 90% viral inhibition in the same cultures. This enhanced T-cell survival (which is similar for CD4 and CD8 cells) was associated with a restoration of T-cell proliferative response to immune stimuli. However, neither TCR/CD3-ligation– nor Fas-ligation–triggered apoptosis was affected by either of the 2 protease inhibitors. A reduction in apoptosis observed after prolonged culture of patient T cells in the presence of the protease inhibitors could result from restored T-cell proliferation. These findings explain the discrepancies between virologic and immunologic responses that are increasingly reported in patients receiving HAART, and may provide insights into the pathogenesis of HIV infection.

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CELLULAR INTERACTIONS IN THE PROLIFERATIVE RESPONSE OF HUMAN T AND B LYMPHOCYTES TO PHYTOMITOGENS AND ALLOGENEIC LYMPHOCYTES

Journal of Experimental Medicine ◽

10.1084/jem.139.6.1553 ◽

1974 ◽

Vol 139 (6) ◽

pp. 1553-1567 ◽

Cited By ~ 114

Author(s):

Hans-Peter Lohrmann ◽

Ligita Novikovs ◽

Robert G. Graw

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

B Cell ◽

T Cell Activation ◽

Proliferative Response ◽

Cell Activation ◽

Human Peripheral Blood ◽

Cellular Interactions ◽

Allogeneic Lymphocytes

In vitro studies were performed to determine the proliferative responsiveness of human peripheral blood thymus-dependent (T) and thymus-independent (B) lymphocytes to phytomitogens and allogeneic lymphocytes. Recombination of T and B cells, with selective inhibition of proliferation of one of the two populations, was used to identify cellular interactions which may contribute to cell proliferation. The distinctive feature of human T lymphocytes to form rosettes with unsensitized sheep erythrocytes was utilized to separate human peripheral blood lymphocytes into highly purified resetting (T) and non-rosetting (B) cells. The proliferative response of these separated lymphocyte subpopulations to various stimulants was assessed from the uptake of tritiated thymidine into DNA. Phytohemagglutinin, concanavalin A, pokeweed mitogen, and allogeneic lymphocytes stimulated separated T cells, whereas no proliferation was observed with the T-cell-depleted B-cell population. This suggests that it is the human T cell which is activated directly by these stimulants. In the presence of T cells (proliferating or nonproliferating), B cells were capable of proliferation following stimulation with phytomitogens, but not in response to histocompatibility antigens. Thus, T-cell-mediated B-cell proliferation contributes to the overall lymphocyte response in phytomitogen-stimulated T + B cell mixtures, but not in human mixed leukocyte cultures. T-cell activation by allogeneic cells required the presence of monocytes; in contrast, the three tested phytomitogens stimulated T cells in the absence of monocytes. This indicates that direct interaction of mitogens with lymphocyte membrane receptors is sufficient to trigger T cells into proliferative response. However, monocytes considerably enhanced the proliferative response of T cells in a dose-dependent fashion; this monocyte-dependent mechanism of T-cell activation was predominant at lower concentrations of phytomitogens, and contributed relatively less at higher mitogen doses. Both, the direct, monocyte-independent, and the indirect, monocyte-dependent T-lymphocyte activation contribute to the total in vitro response of lymphocyte preparations to phytomitogens.

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HIV protease inhibitors restore impaired T-cell proliferative response in vivo and in vitro: a viral-suppression–independent mechanism

Blood ◽

10.1182/blood.v96.1.250 ◽

2000 ◽

Vol 96 (1) ◽

pp. 250-258 ◽

Cited By ~ 52

Author(s):

Wei Lu ◽

Jean-Marie Andrieu

Keyword(s):

T Cells ◽

T Cell ◽

Protease Inhibitors ◽

Peripheral Blood ◽

Proliferative Response ◽

Hiv Protease ◽

Nucleoside Analogues ◽

Hiv Protease Inhibitors ◽

Cell Proliferative Response

Abstract In 99 adults infected with human immunodeficiency virus type 1 (HIV-1) who received highly active antiretroviral therapy (HAART) (including 2 nucleoside analogues and 1 or 2 protease inhibitors) for 1 year, CD4+ and CD8+ T cells (including memory and naive subsets) increased similarly among patients with sustained plasma viral load decrease, transient decrease, or no decrease. A linear correlation was observed between the decrease in serum β2-microglobulin concentration (an independent surrogate marker of HIV disease) and the increase in peripheral blood T-cells (CD4+ and CD8+) counts. In vitro, HIV protease inhibitors indinavir and saquinavir (but not nucleoside analogues) enhanced the survival of patients' peripheral blood T cells at doses that are at least 30-fold lower than those required for achieving 90% viral inhibition in the same cultures. This enhanced T-cell survival (which is similar for CD4 and CD8 cells) was associated with a restoration of T-cell proliferative response to immune stimuli. However, neither TCR/CD3-ligation– nor Fas-ligation–triggered apoptosis was affected by either of the 2 protease inhibitors. A reduction in apoptosis observed after prolonged culture of patient T cells in the presence of the protease inhibitors could result from restored T-cell proliferation. These findings explain the discrepancies between virologic and immunologic responses that are increasingly reported in patients receiving HAART, and may provide insights into the pathogenesis of HIV infection.

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B cell depletion impairs vaccination-induced CD8+ T cell responses in a type I interferon-dependent manner

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-220435 ◽

2021 ◽

pp. annrheumdis-2021-220435

Author(s):

Theresa Graalmann ◽

Katharina Borst ◽

Himanshu Manchanda ◽

Lea Vaas ◽

Matthias Bruhn ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

B Cell ◽

Cell Expansion ◽

De Novo ◽

T Cell Responses ◽

Type I ◽

Cell Responses ◽

T Cell Expansion

ObjectivesThe monoclonal anti-CD20 antibody rituximab is frequently applied in the treatment of lymphoma as well as autoimmune diseases and confers efficient depletion of recirculating B cells. Correspondingly, B cell-depleted patients barely mount de novo antibody responses during infections or vaccinations. Therefore, efficient immune responses of B cell-depleted patients largely depend on protective T cell responses.MethodsCD8+ T cell expansion was studied in rituximab-treated rheumatoid arthritis (RA) patients and B cell-deficient mice on vaccination/infection with different vaccines/pathogens.ResultsRituximab-treated RA patients vaccinated with Influvac showed reduced expansion of influenza-specific CD8+ T cells when compared with healthy controls. Moreover, B cell-deficient JHT mice infected with mouse-adapted Influenza or modified vaccinia virus Ankara showed less vigorous expansion of virus-specific CD8+ T cells than wild type mice. Of note, JHT mice do not have an intrinsic impairment of CD8+ T cell expansion, since infection with vaccinia virus induced similar T cell expansion in JHT and wild type mice. Direct type I interferon receptor signalling of B cells was necessary to induce several chemokines in B cells and to support T cell help by enhancing the expression of MHC-I.ConclusionsDepending on the stimulus, B cells can modulate CD8+ T cell responses. Thus, B cell depletion causes a deficiency of de novo antibody responses and affects the efficacy of cellular response including cytotoxic T cells. The choice of the appropriate vaccine to vaccinate B cell-depleted patients has to be re-evaluated in order to efficiently induce protective CD8+ T cell responses.

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Immunomodulatory effects of different intravenous immunoglobulin preparations in chronic lymphocytic leukemia

Scientific Reports ◽

10.1038/s41598-021-92412-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ana Colado ◽

Esteban Enrique Elías ◽

Valeria Judith Sarapura Martínez ◽

Gregorio Cordini ◽

Pablo Morande ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

Chronic Lymphocytic Leukemia ◽

T Cell Activation ◽

Cell Activation ◽

Lymphocytic Leukemia ◽

Immunomodulatory Effects ◽

Immunoglobulin Preparations

AbstractHypogammaglobulinemia is the most frequently observed immune defect in chronic lymphocytic leukemia (CLL). Although CLL patients usually have low serum levels of all isotypes (IgG, IgM and IgA), standard immunoglobulin (Ig) preparations for replacement therapy administrated to these patients contain more than 95% of IgG. Pentaglobin is an Ig preparation of intravenous application (IVIg) enriched with IgM and IgA (IVIgGMA), with the potential benefit to restore the Ig levels of all isotypes. Because IVIg preparations at high doses have well-documented anti-inflammatory and immunomodulatory effects, we aimed to evaluate the capacity of Pentaglobin and a standard IVIg preparation to affect leukemic and T cells from CLL patients. In contrast to standard IVIg, we found that IVIgGMA did not modify T cell activation and had a lower inhibitory effect on T cell proliferation. Regarding the activation of leukemic B cells through BCR, it was similarly reduced by both IVIgGMA and IVIgG. None of these IVIg preparations modified spontaneous apoptosis of T or leukemic B cells. However, the addition of IVIgGMA on in vitro cultures decreased the apoptosis of T cells induced by the BCL-2 inhibitor, venetoclax. Importantly, IVIgGMA did not impair venetoclax-induced apoptosis of leukemic B cells. Overall, our results add new data on the effects of different preparations of IVIg in CLL, and show that the IgM/IgA enriched preparation not only affects relevant mechanisms involved in CLL pathogenesis but also has a particular profile of immunomodulatory effects on T cells that deserves further investigation.

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T cell-independent antibody-mediated clearance of polyoma virus in T cell-deficient mice.

Journal of Experimental Medicine ◽

10.1084/jem.183.2.403 ◽

1996 ◽

Vol 183 (2) ◽

pp. 403-411 ◽

Cited By ~ 73

Author(s):

E Szomolanyi-Tsuda ◽

R M Welsh

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

Nude Mice ◽

Knockout Mice ◽

Cell Receptor ◽

Genetically Engineered ◽

Scid Mice ◽

Myeloproliferative Disease ◽

Alpha Beta

Polyomavirus (PyV) infection of SCID mice, which lack functional T and B cells, leads to a lethal acute myeloproliferative disease (AMD) and to high levels of virus replication in several organs by two wk after infection. This is in contrast to infection of T cell-deficient athymic nude mice, which are resistant to acute PyV-induced disease and poorly replicate the virus in their organs. This major difference in the virus load and in the outcome of PyV infection between SCID and nude mice suggested that an efficient, T cell-independent antiviral mechanism operates in T cell-deficient, PyV infected mice. To investigate this possibility, mice with different genetically engineered T and/or B cell deficiencies and SCID mice adoptively reconstituted with B and/or T cells were infected with PyV. The results indicated that the presence of B cells in the absence of T cells protected mice from the AMD, and this was accompanied by a major reduction of PyV in all organs tested. Sera from PyV-infected T cell receptor (TCR) alpha beta knockout or TCR alpha beta gamma delta knockout mice contained IgG2a antibodies to PyV. Sera or purified immunoglobulin fractions from PyV-infected TCR alpha beta knockout mice protected SCID mice from the PyV-induced AMD. To our knowledge, this is the first report of an effective T cell-independent antibody response clearing a virus and changing the outcome of infection from 100% mortality to 100% survival.

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