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Biomedical subjects

C S Via

Publications and source records attributed to C S Via.

47 records · Page 3Linked to original sources
PubMed1988

Defective thymic education of L3T4+ T helper cell function in graft-vs-host mice.

Our study investigates the effect of a prior graft-vs-host (GVH) reaction on the subsequent ability of irradiated, bone marrow-re-populated mice to develop T cell function. The results indicate that such GVH-bone marrow transplanted (BMT) mice do not generate CTL responses to trinitrophenyl-modified syngeneic cells (TNP-self), but do generate strong CTL activity to H-2 alloantigens. This selective deficiency in TNP-self CTL response potential appeared as early as 10 days after GVH, and required both L3T4+ and Lyt-2+ donor T cells. The in vitro addition of either soluble Th factors or L3T4-enriched spleen cells from normal mice circumvented the defect in the TNP-self response in GVH-BMT mice. These results indicate that T effector function was not defective, and instead suggest a Th defect. Cell depletion and antibody-blocking, as well as IL-2 production experiments, indicate that the Th defect was selective for L3T4+ Th population and not for Lyt-2+ Th population. This defect in L3T4 Th function is not accounted for by the approximate twofold reduction in L3T4 cell numbers in GVH-BMT mice, because IL-2 production and CTL generation to L3T4-dependent Ag were at least eightfold below control levels. Rather, defective L3T4 Th function appears to be the consequence of a GVH-induced defect in thymic maturation because the defect was corrected in vivo by a neonatal parental thymus graft before irradiation and bone marrow transplantation. This system may be useful for elucidating the role of the thymus in the maturation of Th cells. Our findings raise the possibility that impaired development of T cell function occurring in marrow grafted patients who have undergone a GVH reaction could be partly due to a GVH-induced thymic defect.

Animals↗
PubMed1988

Altered threshold for the induction of graft-versus-host immunodeficiency following murine cytomegalovirus infection. Host and donor contributions.

Acute murine cytomegalovirus (MCMV) infection enhances the ability of parental spleen cells to induce graft-vs.-host immunodeficiency (GVHID) in F1 hybrid mice when the two processes occur simultaneously in the recipient. The present study assessed GVHID as the ability of spleen cells to generate in vitro cytotoxic T lymphocyte responses to trinitrophenyl-modified syngeneic cells. The results indicate that MCMV infection not only reduces the number of parental spleen cells required to induce GVHID, but accelerates the onset of GVHID, which occurs as early as 3 days after cell and virus challenge. To determine whether MCMV infection exerts this synergistic effect primarily through the donor or the host component, we examined the effect of MCMV infection of either donor mice or recipient mice at 3, 10, and 17 days prior to spleen cell transfer. Two weeks after cell transfer, splenocytes were tested for their ability to generate CTL. When donor mice were infected with MCMV three days prior to cell transfer, the ability of donor cells to induce GVHID was reduced. In contrast, MCMV infection of the recipients three days prior to cell transfer increased their susceptibility to GVHID induction. Infection of either donor or host mice 10 days or 17 days prior to parental spleen cell transfer had little effect on the ability to induce or resist GVHID when compared with sham-infected mice. Thus, acute MCMV infection can modulate the severity of GVHID depending on whether it is the donor or the host that is infected. The ability of acute MCMV to alter the course and severity of GVHID may be relevant for human bone marrow transplants in which preceding CMV infection has been associated with chronic GVH. In this setting, CMV may lower the threshold necessary to induce a GVH reaction.

Animals↗
PubMed1987

Role of cytotoxic T lymphocytes in the prevention of lupus-like disease occurring in a murine model of graft-vs-host disease.

The inoculation of B6D2F1 mice with T lymphocytes from the C57BL/6 parental strain induces an "immunosuppressive" graft-vs-host reaction (B6 GVH), whereas inoculation of T cells from the other, DBA/2 parental strain induces an "immunostimulatory" GVH reaction and a lupus-like disease (DBA GVH). The present study compares cytotoxic T lymphocyte (CTL) function in the spleens of these GVH mice as well as differences in the donor inoculum that could account for these different types of GVH. We observed that the B6 GVH induces an immunodeficiency that encompasses CTL precursors (and possibly T helper cells) and results in suppressor cells that abrogate responses to both trinitrophenyl (TNP)-modified self and third party alloantigens. In contrast, the DBA GVH induces only a T helper cell immunodeficiency and results in suppressor cells selective for class II restricted L3T4+ T helper cells. Chimeric T cells were detected in both types of GVH. In the B6 GVH both L3T4+ and Lyt-2+ donor cells were observed, although Lyt-2+ cells predominated. In the DBA GVH, donor T cells were almost exclusively of the L3T4+ phenotype. The lack of appreciable donor Lyt-2+ cells in the DBA GVH can be explained by a defect in the DBA donor inoculum manifested by a naturally occurring two-fold reduction in Lyt-2+ cell numbers as well as a nine-fold reduction in CTL precursors with anti-F1 specificity. T cells in the DBA inoculum, therefore, are predominantly L3T4+. A similar defect induced in B6 donor cells by anti-Lyt2 antibody and complement not only converted the suppressive GVH to a stimulatory GVH, as measured by anti-DNA antibodies, but also resulted in a T cell immune deficiency characteristic of the DBA GVH, i.e., a selective loss of the TNP-self CTL response. Thus the presence or absence of adequate numbers of functioning Lyt-2+ cells in the donor inoculum is correlated with the development of either a suppressive or stimulatory GVH, respectively. That donor Lyt-2+ cells mediate a suppressive GVH through cytolytic mechanisms is evidenced by greater than 70% reduction in B6 GVH spleen cell numbers and readily demonstrable anti-F1 CTL activity by these spleen cells despite an inability to generate anti-allogeneic or anti-TNP self CTL activity even in the presence of added T helper factors.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Interstitial pneumonitis during murine cytomegalovirus infection and graft-versus-host reaction. Characterization of bronchoalveolar lavage cells.

Acute murine cytomegalovirus (MCMV) infection alters the course of graft-vs-host (GVH) disease involving major histocompatibility (MHC) antigens and induces interstitial pneumonitis. F1 (B10 x B10.BR) mice given 20 x 10(6) B10.BR spleen cells and MCMV (1 x 10(5) plaque-forming units [PFU]) develop severe, diffuse pneumonitis not seen with either MCMV or GVH alone. As one index of the host immune processes operating in the lungs during MCMV/GVH pneumonitis, we examined the types of cells recovered from the lung by bronchoalveolar lavage (BAL) during pneumonitis. During MCMV/GVH pneumonitis, the total cells recovered significantly increased, due primarily to an influx of Thy 1.2 lymphocytes. Characterization of cells using multiparameter flow cytometric analysis revealed that greater than 80% of all BAL cells were Thy 1.2-positive lymphocytes of donor origin. In addition, donor Thy 1.2-positive cells were of both the L3T4+ (43% of BAL cells) and Lyt 2+ (38% of BAL cells) phenotype. Thus, MCMV infection during GVH to MHC antigens induces interstitial pneumonitis, characterized by an influx of T lymphocytes (both helper and suppressor/cytotoxic) from the donor. The antigenic specificity of these cells is not known.

Animals↗
PubMed1986

A model for the selective loss of major histocompatibility complex self-restricted T cell immune responses during the development of acquired immune deficiency syndrome (AIDS).

Functional analyses of peripheral blood leukocytes (PBL) from high risk HTLV-III antibody-negative and antibody-positive donors, as well as from patients with acquired immune deficiency syndrome (AIDS), lymphadenopathy syndrome (LAS), and AIDS-related complex (ARC) were performed by the in vitro generation of cytotoxic T lymphocyte (CTL) and proliferative responses to the HLA self-restricted antigens of influenza virus (S + X) and to nonself restricted HLA alloantigens (ALLO). All 40 antibody-negative donors tested responded to both S + X and ALLO in the CTL response, whereas six of 14 antibody-positive, two of three LAS, four of five ARC, and seven of 17 AIDS patients exhibited a selective absence of CTL to S + X, but generated normal or elevated CTL responses to ALLO. Of the remaining 10 AIDS patients, nine did not respond to either S + X or ALLO, and one responded to both S + X and ALLO. A similar selective loss of the proliferative response to S + X was found. We also observed antibody-positive donors who initially generated CTL responses to S + X and ALLO, but lost the S + X response as a function of time. We were able to restore the selective loss of S + X CTL activity in vitro by the addition of IL 2 and, to some extent, by co-stimulation with S + X plus ALLO. Depletion of CD4+ T helper cells and removal of autologous antigen-presenting cells from the PBL of healthy antibody-negative donors indicated that distinct T helper cell subsets exist in human PBL, and that S + X responses must use a CD4+ T helper population, whereas ALLO responses can utilize an alternate CD4- T helper pathway. A model is presented indicating the selective depletion of CD4+ T helper function in the developmental stages of AIDS. The functional test for T helper activity to self restricted antigens may be the earliest indicator of immune functional loss in the development of AIDS, and may precede a reduction in the absolute number of CD4+ cells.

AIDS-Related Complex↗
PubMed1985

Weekly pulse methotrexate in rheumatoid arthritis. Clinical and immunologic effects in a randomized, double-blind study.

Twelve patients with refractory rheumatoid arthritis were treated with weekly pulse methotrexate in a double-blind, placebo-controlled, crossover study. After 13 weeks of therapy, patients receiving methotrexate showed greater improvement, judged by degree of joint swelling and tenderness, duration of morning stiffness, and subjective assessments of clinical condition, compared to those receiving placebo (p less than or equal to 0.002). This improvement was associated with a decrease in sedimentation rate and decreases in levels of IgG, IgM, and IgA; no changes were seen in serum rheumatoid factor titer or complement protein levels. Proportions of mononuclear cell subsets that were abnormal before treatment (decreased percentage of total T cells, increased percentage of monocytes) improved toward normal after therapy with methotrexate. However, no changes were seen in elevated pretreatment Leu-3/Leu-2 ratios, in in-vitro proliferative responses of lymphocytes to mitogens, or in immunoglobulin secretory responses to pokeweed mitogen. Weekly pulse methotrexate is effective in the short-term treatment of refractory rheumatoid arthritis. Little evidence for cellular immune suppression was associated with this clinical benefit.

Arthritis, Rheumatoid↗
PubMed1984

Rheumatoid arthritis and membranous glomerulonephritis: a role for immune complex dissociative techniques.

Although controversial, several reports have linked rheumatoid arthritis (RA) with membranous glomerulonephritis (MGN). In none of these studies was an infectious etiology such as hepatitis B virus (HBV) thoroughly pursued. We evaluated a patient with classic RA and MGN unassociated with nephrotoxic drugs. Although negative by routine serological methods, hepatitis B surface antigen was eventually demonstrated in the serum, using immune complex dissociative techniques, and in the renal glomeruli, using tissue immunofluorescence. A review of the literature provides no conclusive evidence for a causal relationship of RA to MGN. The renal pathogenic potential of HBV, however, is well documented. Future use of immune complex dissociative techniques and tissue immunofluorescence may be of value in clarifying otherwise unexplained MGN in the setting of RA.

Adult↗
PubMed1984

Direct stimulation of neutrophil oxygenation activity by serum from patients with systemic lupus erythematosus: a relationship to disease activity.

Sera from patients with systemic lupus erythematosus (SLE) directly stimulate polymorphonuclear leukocyte (PMNL) oxygenation activity as measured by luminol dependent chemiluminescence (CL). The stimulatory capacity of a serum, expressed as percent PMNL chemiluminescence (%CL), was calculated by dividing the integral CL response to the serum by the integral CL response to a standard stimulus, opsonified zymosan. Testing was performed on 50 sera obtained serially from 8 SLE patients and on 14 sera from 11 controls. Sera from SLE patients in remission and controls were nonstimulatory with mean %CL +/- SE values of 3.1 +/- 0.7 and 3.5 +/- 0.9, respectively. Sera obtained from the SLE patients during active disease yielded a mean %CL value of 26.6 +/- 9.0. The stimulatory capacity of SLE serum was concentration dependent and enhanced by adding normal serum complement. The CL response correlated with serological measures of SLE activity such as antibodies to double stranded DNA (p less than .0001) and Clq binding immune complexes (p less than .001). Thus, during active SLE, PMNL may become metabolically activated by exposure to serum containing immune complexes and possibly other factors. PMNL activation may contribute to the development of vasculitis, leukopenia, and susceptibility to infection. Our CL approach allows sensitive in vitro assessment of the phlogistic properties of serum to monitor SLE disease activity.

Adolescent↗