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Biomedical subjects

P C Doherty

Publications and source records attributed to P C Doherty.

At least 163 records · Page 9Linked to original sources
PubMed1988

Contributions of host and donor T cells to the inflammatory process in murine lymphocytic choriomeningitis.

The severe inflammation characteristic of the infection of adult mice with murine lymphocytic choriomeningitis virus (LCMV) is induced earlier in unsuppressed, virus-infected recipients by the adoptive transfer of class I MHC-compatible, CD4- CD8+ LCMV-immune spleen cell populations. The time to onset of fatal LCM may also be slightly diminished, though not to the extent that would be expected from the enhanced kinetics of the extravasation of cells into cerebrospinal fluid. The development of symptoms is thus not solely related to the magnitude of the inflammatory process. The majority of the T lymphocytes in the inflammatory exudate are of host origin and have the size characteristics of resting cells, while the minority population of donor T cells show more of a lymphoblast morphology. The findings are consistent with the idea that relatively few CD8+ virus-immune effectors trigger an inflammatory process which consists largely of secondarily recruited host T cells and monocyte/macrophages.

Animals↗
PubMed1988

Virus-specific memory T cells are Pgp-1+ and can be selectively activated with phorbol ester and calcium ionophore.

Memory lymphocytic choriomeningitis virus (LCMV)-immune cytotoxic T-lymphocyte precursors (CTLp) can be stimulated to proliferate and to mediate specific cytotoxic activity following incubation with phorbol myristate acetate (PMA), calcium ionophore (CaI), and interleukin 2 (IL-2). This protocol can be used to selectively induced virus-specific CTL activity under both bulk culture and limiting dilution conditions, in the absence of added antigen. There is no concurrent stimulation of alloreactive CTLp. Proliferation of the effector Lyt-2+ population in medium containing PMA and CaI requires L3T4+ cells, which can be replaced by adding IL-2, and the development of cytotoxicity is totally IL-2 dependent. The LCMV-specific memory T cells are also characterized by the expression of the Pgp-1 (Ly24) glycoprotein. The availability of this marker, together with the capacity to selectively stimulate primed CTLp in the absence of antigen, should greatly facilitate the analysis of T-cell memory in virus infections.

Animals↗
PubMed1988

Immunogenetic analysis of cellular interactions governing the recruitment of T lymphocytes and monocytes in lymphocytic choriomeningitis virus-induced immunopathology.

The Lyt2+ class I major histocompatibility complex (MHC)-restricted virus-immune T cells that induce murine lymphocytic choriomeningitis (LCM) are targeted onto radiation-resistant cells in the central nervous system of virus-infected mice. The use of appropriate bone marrow radiation chimeras as LCM virus-infected, (immunosuppressed recipients for immune T-cell transfer has established that, though bone marrow-derived cells can stimulate virus-specific cytotoxic T lymphocytes (CTL) in spleen, they do not reconstitute the barrier to T-cell recruitment from blood to cerebrospinal fluid. This is true for chimeras made up to 8 months previously, even though the inflammatory monocytes and macrophages in such chimeras are all of donor bone marrow origin. Radiation-resistant cells in the spleens of these chimeras are also still able to further stimulate virus-immune CTL. There is no requirement for H-2 compatibility between virus-immune T lymphocytes and secondarily recruited monocytes, or T cells of an inappropriate specificity. The key event in LCM immunopathology may thus be localization of T cells to the antigen-presenting endothelium in brain, leading to the secretion of mediators that promote the nonspecific recruitment of monocytes and other T cells.

Age Factors↗
PubMed1988

Inhibition of allergic encephalomyelitis by the iron chelating agent desferrioxamine: differential effect depending on type of sensitizing encephalitogen.

Induction of experimental allergic encephalomyelitis (EAE) in Lewis rats by injection of guinea pig (GP) spinal cord homogenate (SCH) plus adjuvant (SCH-CFA) can be inhibited by treatment with the iron chelating agent desferrioxamine (DFOM). Interestingly, induction of EAE with purified myelin basic protein (BP-CFA) is not inhibited with DFOM. This dichotomy does not appear to be due to any quantitative differences in the two inocula since minimal clinical EAE produced by threshold levels of BP is not inhibited with DFOM. Passive EAE is not inhibited irrespective of the type of encephalitogen used to sensitize the donors. This suggests that the inhibitory effect of DFOM is acting on the afferent limb of the immune response to SCH-CFA. Injection of BP-CFA and SCH-CFA into the same site, mixing BP with central nervous system (CNS) lipids, or incorporating BP into liposomes, all induce EAE which can be partially inhibited by treatment with DFOM. These results support the hypothesis that the close association of lipids with the encephalitogen (i.e. BP) in SCH required extensive lipid breakdown before adequate antigen presentation can occur, and it is at this level that DFOM exerts its inhibitory effect.

Animals↗
PubMed1988

Lethal vaccinia infection in cyclophosphamide-suppressed mice is associated with decreased expression of Thy-1, Lyt-2 and L3T4 and diminished IL-2 production in surviving T cells.

Prior treatment of C57BL/6J mice with 300 mg/kg of cyclophosphamide (Cy) converts a subclinical infection with vaccinia virus to a lethal disease. This is accompanied by a loss of more than 80% of spleen cells and a decreased capacity, on a cell-for-cell basis, to develop virus-immune cytotoxic T lymphocytes (CTL), although the frequency of CTL precursors among surviving T cells is not greatly modified. Phenotypically, the surviving T cells express low levels of cell-surface Thy-1, Lyt-2 and L3T4 and, upon stimulation, are less able to produce IL-2 for more than 1 week following Cy treatment. The defect in capacity to generate CTL effectors both in vitro and in vivo can be corrected by providing an exogenous source of IL-2. These experiments indicate that a single dose of Cy induces changes in T cells that persist throughout the development of an immune response. Such effects are in accordance with the known property of Cy to mediate DNA damage.

Animals↗
PubMed1987

Phenotypic analysis of the inflammatory exudate in murine lymphocytic choriomeningitis.

The massive inflammation of the cerebrospinal fluid (CSF) which occurs in adult mice injected with lymphocytic choriomeningitis virus (LCMV) has been analyzed by flow microfluorometry (FMF). The great majority of the T cells detected by direct examination of freshly obtained CSF were found to be Lyt-2+, with an almost total absence of L3T4+ lymphocytes. The Lyt-2/L3T4 ratio of lymphocytes in blood was within normal limits. Predominance of the Lyt-2+ subset was confirmed by culturing the CSF cells after mitogenic stimulation. In addition, the T lymphocytes in CSF of cyclophosphamide-suppressed, virus-infected recipients that had been injected 4 d previously with LCMV-immune spleen cells were almost entirely donor Lyt-2+ cells, while the nonlymphoid elements were exclusively of host origin. However this pattern of donor and host T cell distribution was reversed when the LCMV-infected recipients were not immunosuppressed. The frequency of LCMV-specific CTL precursors in CSF taken immediately before the development of symptoms was as low as 1:3,000 cells. Thus most of the T lymphocytes extravasating into the CSF of mice with LCM are passive participants recruited as a consequence of the function of relatively few LCMV-specific effector T cells. The dominance of the Lyt-2+ T cell subset in the CSF of mice with LCM is intriguing.

Animals↗
PubMed1987

Expression of Pgp-1 (or Ly24) by subpopulations of mouse thymocytes and activated peripheral T lymphocytes.

The expression of Pgp-1 (Ly24) by subpopulations of thymocytes was investigated and a subpopulation of Lyt-2-/L3T4-/J11d- thymocytes was identified which contained significant numbers (80%) of Pgp-1+ cells. Among freshly isolated lymph node T cells but not cortisone-resistant thymocytes, Pgp-1 expression was heterogeneous. Stimulation of T lymphocytes with either concanavalin A or the combination of phorbol myristate acetate plus calcium ionophore resulted in increased Pgp-1 expression which was found to be regulated independently of DNA synthesis and interleukin 2 receptor expression. T cells in the cerebrospinal fluid exudate of mice infected with lymphocytic choriomeningitis virus were also found to be Pgp-1+.

Animals↗
PubMed1987

Anti-asialo GM1 eliminates both inflammatory process and cytotoxic T-cell function in the lymphocytic choriomeningitis adoptive transfer model.

The induction of severe inflammatory process and fatal neurological disease by transfer of lymphocytic choriomeningitis virus (LCMV)-immune T cells into cyclophosphamide (Cy)-suppressed LCMV-infected mice is greatly inhibited by treatment of these recipients with antibody to the asialo GM1 ganglioside (anti-ASGM1). Examination of cytotoxic activity in lymphoid tissue of the Cy-suppressed recipients at 72 hr after cell transfer revealed that anti-ASGM1 treatment prevented the development of the cytotoxic T lymphocyte (CTL) response, even though the dose of antibody used did not significantly decrease CTL generation in unsuppressed mice. Abrogation of CTL activity was also observed following antibody treatment of NK-deficient (bg/bg) Cy-suppressed recipients, indicating that the anti-ASGM1 was unlikely to be operating via removal of NK cells that are in some way involved in the development of the CTL response. The possibility that anti-ASGM1 may act directly on T cells should be considered in all protocols involving the use of this reagent in immunosuppressed mice.

Animals↗
PubMed1987

The acute inflammatory process in murine lymphocytic choriomeningitis is dependent on Lyt-2+ immune T cells.

Virus-immune spleen cells induce fatal immunopathology following adoptive transfer into adult C57B1/6J mice that have been infected with lymphocytic choriomeningitis virus (LCMV) and immunosuppressed with cyclophosphamide. This is accompanied by the development of potent cytotoxic T-lymphocyte (CTL) activity of donor origin in the recipient spleen. Both the capacity to trigger the acute meningitis observed at 72 hr and to generate CTL effectors in lymphoid tissue are completely abrogated by the removal of Lyt-2+ cells from the donor population. However a lower level of inflammatory process in the central nervous system may emerge, in the absence of significant CTL function in recipient spleen, by 5 days after transfer of the Lyt-2-depleted cell population. Treatment of the transferred cells with antibody to the L3T4 marker does not reduce either the severity of inflammation or the level of CTL effector function in the recipient. Thus Lyt-2+ cells are required for the acute, fatal immunopathology characteristic of LCM, but it is not clear that in a more chronic situation, they are the sole effectors capable of triggering inflammatory process in this disease.

Animals↗
PubMed1987

Flavivirus-specific murine L3T4+ T cell clones: induction, characterization and cross-reactivity.

Murine T cell clones specific for the Kunjin (KUN), West Nile (WN) and Murray Valley encephalitis (MVE) flaviviruses were generated in vitro following priming in vivo. Clones were isolated by limiting dilution and maintained in culture with antigen stimulation and interleukin-2(IL-2). The cells were characterized as having the Thy 1+, L3T4+ and Lyt 2- phenotype by immunofluorescence. All clones proliferated strongly and secreted high levels of IL-2 and IL-3 in response to homologous antigen. Both KUN- and WN-specific clones showed extensive cross-reactivity to KUN and WN antigen, but recognized MVE to a lesser extent. In contrast, MVE-specific clones cross-reacted strongly with both KUN and WN. These data show that antigen-specific, major histocompatibility complex-restricted L3T4+ T cells are generated during flavivirus infection and are cross-reactive for viruses of the same subgroup.

Animals↗
PubMed1986

Anti-Thy-1 plus complement-treated, cultured bone marrow cells resemble fetal thymocytes in killer cell function and marker expression.

Anti-Thy-1.2 plus complement treated bone marrow cells were tested after short-term culture for their ability to lyse allogeneic target cells. Significant lytic activity was generated after 9 days, and required both CAS and splenic or PEC feeders as culture supplements. Allogeneic as well as syngeneic-specific cytotoxic cells were generated polyclonally under such conditions, and could be separated by using limiting dilution protocols. When 65 clones were tested for lytic activity toward three targets bearing H-2k, H-2d, and H-2b haplotypes, respectively, only two clones lysed all three targets; 53 clones showed specificity toward one target only. Targets low in class I H-2 expression were lysed only minimally compared with high H-2 expressors. Allogeneic-kill by C57BL/6 bone marrow cells grown on AKR feeder cells was destroyed by treating effectors with anti-Thy-1.2, but not anti-Thy-1.1, antibody plus complement, suggesting 1) a de novo generation of surface Thy-1 during culture and 2) that effectors were derived from bone marrow, but not feeder, populations. Partial inhibition of kill occurred by treatment of effectors with anti-asialo-GM1 (approximately 80%), anti-Lyt-2 (approximately 60%), or anti-Ly-5.1 (approximately 30%) antibodies plus complement; treatment of effectors with anti-L3T4 or anti-NK-1.1 antibodies plus complement had no effect. When precursor populations were treated with either anti-Thy-1.2 alone or a combination of anti-Thy-1.2 and anti-Lyt-2 antibodies plus complement, killers were easily demonstrated. However, the addition of an anti-asialo-GM1 antibody plus complement treatment before culture abolished function. The characteristics of these effectors showed a resemblance to those described previously for day 14 to 17 fetal thymocytes, designated pCTL.

Animals↗
PubMed1986

Role of the major histocompatibility complex in targeting effector T cells into a site of virus infection.

Bone marrow radiation chimeras have been used as virus-infected, cyclophosphamide-suppressed recipients to analyze the major histocompatibility complex (MHC) restriction constraints on the adoptive transfer of lymphocytic choriomeningitis by immune T cells. The basic protocol employed [(A X B)F1----(A X C)F1] chimeras, where A, B, C are different MHC haplotypes, and the establishment of appropriate chimerism was measured by the capacity of, for instance, the transferred A, T cells to generate MHC-restricted, virus-specific cytotoxic T lymphocytes (CTL) in the spleen of the [(A X B)F1----(B X C)F1] recipients. The experiments show quite clearly that maximal inflammatory process is only induced when donor bone marrow, irradiated recipient and transferred T cells share at least one MHC haplotype. Compatibility of the T cells and the radiation-resistant phenotype alone in, for instance, transfer of C immune lymphocytes into [(A X B)F1----(B X C)F1] recipients produced little inflammation if the chimeras had been established for at least 10 weeks. These results are compatible with a model which proposes that the transferred T cells first replicate in MHC-compatible lymphoid tissue and are then targeted onto the appropriate MHC plus virus expressed on cells in the blood-cerebrospinal fluid (CSF) barrier. An alternative postulate, that all that is required for the development of inflammatory process is MHC-restricted T cell replication in lymphoid tissue, with subsequent nonspecific localization to the central nervous system (CNS), was explored by transferring B, immune T cells into [(A X B)F1----A] recipients. The finding was that H-2b effectors did not cause any meningitis in [H-2kXb F1----H-2k] recipients, though potent H-2b-restricted CTL were generated in the spleens of comparable chimeras. However, in the H-2k immune----[H-2kXbF1----H-2b] transfer there was evidence of moderate inflammation that was about 9 times less severe than that caused by the H-2b effectors in comparable recipients. This indicates that, for maximal inflammatory process to occur, the T cells must encounter MHC-compatible, virus-infected cells in the CNS, with the effect being absolute in one strain combination and partial in another. Possible mechanisms underlying this divergence are discussed.

Animals↗
PubMed1986

Immunohistochemical analysis of the involvement of F4/80 and Ia-positive macrophages in mouse liver infected with lymphocytic choriomeningitis virus.

The distribution of cells bearing the F4/80 macrophage marker and class II MHC glycoproteins has been analyzed in the livers of mice infected with viscerotropic LCMV. The number of F4/80+ macrophages in the liver increases greatly during infection. Much of this is due to the localization of F4/80+ Ia+ monocytes, large numbers of which attach to the walls of the sinuses and the central and hepatic veins. Numerous lymphocytes are also observed in the sinusoids, frequently in close association with macrophages. The lymphocytes tend to move on from this intravascular location, while the macrophages remain. Foci of F4/80-Ia- mononuclear cells (probably T lymphocytes) are found both in the liver parenchyma and in locations that are obviously perivascular. The most prominent of these lymphocyte cuffs are located in the region of the portal triad. Infiltration of the lymphocyte foci with F4/80+ Ia+ elements occurs late, concurrent with evidence of cell death within the lesion. The dissociation in the focal accumulations of lymphocytes and monocyte/macrophages early in the disease process is both striking and unforeseen.

Animals↗