Reginald M. Gorczynski

Analysis of subpopulations of glass-adherent mouse skin cells controlling resistance/susceptibility to infection with Leishmania tropica, and correlation with the development of independent proliferative signals to Lyt-1+/Lyt-2+ T lymphocytes

Abstract A comparison has been made between the course of Leishmania tropica infection of BALB/ c, CBA, and (BALB/c × CBA)F1 mice in vivo and the growth of the parasite in isolated adherent skin cells in vitro. The susceptible phenotype of the BALB/c mouse was reflected in an innate susceptibility of a discrete subpopulation of adherent skin cells to permit extensive and prolonged growth and replication of the parasite in tissue culture. When cells infected in culture were used to stimulate proliferation of immune lymphocytes from “cured” mice, the skin cells of susceptible BALB/c mice were deficient in their ability to induce proliferation of lymphocytes of BALB/c, CBA, or BCF1 origin (all immunized in the appropriate bone marrow reconstituted irradiated BCF1 hosts). In contrast, these skin cells were able to induce proliferation of immune lymphocytes if the L. tropica antigen source used was a soluble excreted extract (EF), rather than that produced by a live parasite infection. Stimulation of naive lymphocytes using an infected adherent skin cell population from BALB/c mice was found to produce a cell population(s) (Thy-1.2+, Lyt-2+ and including some Lyt-1+ cells) able to inhibit subsequent sensitization of normal BCF1 lymph node cells by L. tropica antigens. The susceptibility of the BALB/c mouse in vivo thus may be attributable to the early contact of T-lymphocyte subsets in BALB/c mice with the high-antigen load maintained in this discrete skin cell population. These particular skin cells were also found to express low levels of Ia antigens.

Factors Involved in the Classical Conditioning of Antibody Responses in Mice

There is a great deal of evidence to support the contention that the immune response in mammals to foreign antigens is exquisitely regulated by the immune system itself, and by factors produced by cells associated directly or indirectly with the effects of immune stimulation (1). Amongst the former we could consider the intricacies of a network model for immunoregulation (2), while amongst the latter for instance one could cite evidence for an effect of hormones, interleukins and products of arachidonic acid metabolism on immune responses (3–5), We (6) and others (7–11) have been interested, at the whole organism level, for any evidence which would support the notion that during immunomodulation, an organism can make some form of an association between non-antigenic environmental cues (a conditioned stimulus, CS) and a physiological stimulus known to perturb the immune system in a predictable way (an unconditioned stimulus, US). Thereafter presentation of the CS alone might then produce a physiological response (a conditioned response, CR) analogous to that initially evoked by the US itself (an unconditioned response, UR).

Immunization of susceptible BALB/c mice against Leishmania braziliensis,: I. Resistance induced using as immunogen adherent or nonadherent cells from infected mice☆

Strategies to produce resistance to infection with Leishmania braziliensis in BALB/c mice are described. Mice infected with virulent parasites were used as spleen cell donors (adherent/nonadherent cells) with which to immunize naive recipients which were themselves later challenged with the organism. Immunization with both adherent and nonadherent spleen cells (but not serum) in the presence of adjuvant led to protection. In the former case it seems that an immunogenic form of parasite antigen presented in the context of MAC-1+ adherent cells was responsible. In contrast immunization with nonadherent spleen cells depended upon the presence of Thy-1.2+ Lyt-1+ cells in the spleen cell preparation from infected animals. Immunization with adherent cells, but not with nonadherent cells, led to the development of a population of Thy-1.2+ spleen cells capable of adoptively transferring resistance to naive mice.

Reactivity of T-cells from patients with rheumatoid arthritis to anti-CD3 antibody

The ability of an anti-CD3 monoclonal antibody (OKT3) to induce proliferation was examined in peripheral blood mononuclear cells (PBM) from 30 patients with rheumatoid arthritis (RA). Controls consisted of 10 patients with osteoarthritis, 12 patients with psoriatic arthritis, and 12 healthy subjects. The results revealed enhanced PBM reactivity in patients with active RA relative to inactive RA patients and all control groups. PBM of patients with mild/moderate clinical disease activity exhibited augmented anti-CD3 reactivity while those with severe disease demonstrated impaired reactivity. Enhanced reactivity was also observed in the active RA group using another anti-CD3 monoclonal antibody (Leu-4). Differences in anti-CD3 dose-response or time kinetics could not account for the results. Studies of enriched T-cell preparations revealed a markedly enhanced anti-CD3 reactivity of RA T-cells relative to normal control T-cells. Monocyte/T-cell mixing experiments revealed no enhanced reactivity of RA monocytes in the anti-CD3 response. RA T-cell preparations depleted of monocytes by limiting dilution reacted significantly more to anti-CD3 in the presence of IL-2 relative to controls. The enhanced reactivity could be accounted for in part by hyperreactivity of the OKT8-bearing subpopulation of T-cells.

Ontogeny of diversity in the receptor repertoire of murine cytotoxic lymphocytes: I. Comparison of recognition patterns of activated T cells of B10.D2 and B10.BR mice of different ages and analysis of changes in F1 hybrid and bone marrow radiation chimeras☆

Abstract Cytotoxic T lymphocyte precursors (CTLp) from B10.D 2 , B10.BR, and (B10.D 2 × B10.BR)F 1 mice of different ages have been activated by irradiated “wild-type” H2K b antigens (from B10.A(3R) mice) under limiting dilution conditions such that cytotoxic cells in responder wells represent the progeny of a single CTLp. After expansion in the presence of IL 2 and irradiated C57B1/6Kha spleen cells the contents of each well were divided into equal aliquots and tested for lysis with a panel of selected H2K b mutant targets. As has been observed for the murine B-cell repertoire, there seems to be substantially more homogeneity in the neonatal allo-T-cell repertoire than in the adult mouse. Furthermore, while the adult F 1 repertoire is markedly distinct from that expressed by either parental T-lymphocyte pool, the neonatal repertoire apparently reflects a relatively accurate composite of each parental population, codominantly expressed. These data, combined with studies of adult bone marrow radiation chimeras, suggest that during development of the adult T-lymphocyte repertoire from the initially expressed restricted (germ-line?) recognition specificities, somatic diversification driven by environmental (MHC?) antigenic determinants occurs. In addition to this ontogenetic development, during senescence another “regulation” of the repertoire becomes apparent, and once more the heterogeneity of recognition specificities is diminished. Nevertheless, the homogeneity seen in aged mice does not represent a simple return to the expression of the limited number of allo-specificities encoded in the neonatal repertoire.

Analysis of early events occurring during neonatal induction of tolerance to histoincompatible cells in mice.

Abstract Mice have been analyzed at different times post neonatal inoculation of F 1 hybrid lymphoid cells for their ability to respond to foreign MHC antigens expressed on the tolerizing cell population, and to impart that response phenotype to normal adult spleen cells. At early times following neonatal challenge with F 1 spleen cells all mice produced serum immunoglobulins of F 1 donor origin which inhibited the response of normal adult cells. The antigenic specificity of the inhibitory factors suggests a role for an antireceptor antibody in the inhibition seen, and the presence of such serum-mediated inhibition is indicative of (and may be causally related to) the late appearance of a cell-mediated suppressor mechanism in these mice.

Macrophage heterogeneity and Ir-gene control as factors involved in the immune response of guinea pigs to infection with Leishmania enrietti☆

Abstract Macrophages from strains 2/N, 13/N, and (2 × 13)F 1 , guinea pigs have been fractionated by velocity sedimentation and the various subpopulations used as target cells for infection by Leishmania enrietti . The data presented show: (i) that the ability of infected macrophages to support the subsequent growth and replication of the parasite varies according to the cell subpopulation examined, (ii) that different subpopulations differ in their capacity to promote lymphocyte proliferation from lymph node cells of a guinea pig which have recovered from a primary lesion, (iii) that lymphocyte proliferation depends upon presentation of leishmanial antigens in the context of products of the original I-region-coded genes present during the initial ( in vivo ) infection and, (iv) that in immune animals, changes occur in terms of the ability of the macrophages to promote lymphocyte proliferation, but not apparently in terms of their ability to support parasite growth in vitro .

Alterations in lymphocyte recognition repertoire during ageing. I. Analysis of changes in immune response potential of B lymphocytes from non-immunized aged mice, and the role of accessory cells in the expression of that potential

The repertoire of specificities recognized by endogenous plaque-forming cells of young or aged mice has been examined, as well as the repertoire of specificities represented by mitogen-activated B cells of those animals. Significant changes occur in both polyclonal endogenous plaque-forming cells and polyclonal B cell responsiveness, as well as reactivity for antigens expressed on bromelain-treated mouse erythrocytes and mouse Ig-coupled sheep erythrocytes. Adoptive transfer experiments suggest that these changes reflect a role for the differentiative environment in the regulation of the B cell recognition repertoire. Additional analysis of changes in antigen-presenting cells in aged mice suggest that alterations in the manner of presentation of environmental antigens in vivo may control the expressed B cell repertoire. Indeed, under experimental conditions it has proven less easy to induce B cell/macrophage restriction (for antigen presentation and induction of antibody formation) in cells of old animals than in cells of younger mice.

Graft-versus-host disease in murine bone marrow transplantation. II: Modulation of acute and chronic GVHD in mice receiving bone marrow allografts pretreated with immunosuppressive factor derived from a human T cell line

BALB/c bone marrow treated with monoclonal anti-Thy 1.2 antibody and complement is unable to produce prolonged hemopoietic repopulation and survival when transplanted to lethally-irradiated allogeneic CBA recipient mice. Preincubation of the antibody treated bone marrow cells with an immunosuppressive factor (SAF) derived from a 6-thioguanine resistant cell line, itself derived from the human T cell line CEM, in contrast, allowed those bone marrow cells to produce a state of chimerism and long term survival. Parameters designed to gauge the degree of graft-versus-host reactivity (GVHR) in these animals suggested that acute GVHR was abolished with this procedure. Moreover, defining chronic GVHD as associated with abnormally high spontaneous proliferation of splenic cells, elevated anti-host mixed lymphocyte reactivity, or elevated serum immunoglobulin levels (in all cases when compared with the syngeneically repopulated BALB/c----BALB/c), our data suggest that preincubation with SAF modified chronic GVHD also.

Alteration of allospecific T-cell receptors after differentiation from prethymic precursor cells in semiallogeneic environments

Abstract Murine bone marrow cells (strain A) have been allowed to differentiate in vivo in syngeneic (A) or semiallogeneic hosts (A × B) to produce mature splenic T lymphocytes. After stimulation of these cells with irradiated allogeneic (C) spleen cells in tissue cultures, the cytotoxic T-cell blasts (CTL) were purified by velocity sedimentation and used to immunize (A × C) F 1 hybrid mice, to produce antisera recognizing the receptor structure (for C) on the relevant A cytotoxic cells (and their precursors). Using these sera we have been able to show that the T-cell receptor for alloantigen C on strain A cytotoxic precursor lymphocytes (CTLp) seems to differ according to the host environment in which those T cells differentiate from immature bone marrow precursors.