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Biomedical subjects

R I Mishell

Publications and source records attributed to R I Mishell.

36 records · Page 2Linked to original sources
PubMed1975

Differential regulatory effects of accessory cells on the generation of cell-mediated immune reactions.

Conditions for the in vitro generation of cell-mediated immunity to H-2 and non-H-2 alloantigens by mouse spleen cells were compared to conditions for generation of in vitro humoral immunity to sheep red cells. Normal spleen cells grown in standard or allogeneic cell-conditioned media developed strong cellular responses to H-2 antigens but little or no response to non-H-2 antigens. Subpopulations of spleen cells from which the adherent cells had been removed generated strong cellular responses to both H-2 and non-H-2 antigens, provided the cells were cultured in conditioned media. Both cellular responses were shown to be mediated by T cells. Accessory cells from the peritoneum and/or spleen differentially inhibited the non H-2 cellular responses at doses which did not inhibit humoral responses.

Animals↗
PubMed1975

Sera and the in vitro induction of immune responses. I. Bacterial contamination and the generation of good fetal bovine sera.

More than 200 samples of pooled fetal bovine sera (FBS) were tested to determine their capacity to support primary immune responses by cultured mouse spleen cells. Less than 10% of the FBS samples were fully supportive; the majority of the samples were moderately to very deficient. Several lines of evidence suggest that bacterial contamination during the processing of sera plays a major role in determining which sera are supportive. Serum samples known to have been temporarily contamined during processing were strongly supportive. Samples of FBS which were likely never to have been contaminated were deficient. Bacteria from a specific lot of supportive serum converted a very deficient serum into one which was supportive. Several mechanicsms by which bacteria could effect sera are discussed.

Animals↗
PubMed1975

Sera and the in vitro induction of immune responses. II. Inhibitory effects of newborn calf sera on primary humoral responses.

The effect of newborn calf (NBC) sera on the in vitro generation of immune responses were studied. NBC sera inhibited the generation of primary humoral responses to SRBC. The inhibitory activity was dose-dependent and diluted out rapidly. Adding inhibitory doses of NBC serum to test cultures at zero or 24 hr resulted in approximately the same amount of inhibition. Pulsing experiments showed that the test cultures were most sensitive to the inhibitory effects of NBC serum during the 24- to 48-hr period. In contrast to its inhibitory effects on primary humoral responses, NBC sera supported the in vitro generation of secondary humoral responses and significantly increased the responses of some of these over control levels. We found that sera obtained from newborn calves before nursing were not inhibitory for primary responses but sera obtained from the same calves 7 days later did inhibit these responses. We postulate that the inhibitory effects of NBC sera may represent a physiologic control mechanism which becomes active when immunologic maturity develops and that it possibly involves the inactivation of cell mediators.

Animals↗
PubMed1975

Functional deficiency of splenic adherent cells in New Zealand black mice.

New Zealand Black (NZB) mice hyporespond after in vitro immunization to sheep erythrocytes but not after in vivo immunization. The difference between in vitro and in vivo immunization was found to involve a non-antigen-specific change in the spleen which occurs in vivo soon after priming. Adherent spleen cells from young NZB or control strain mice were compared in their ability to cooperate with nonadherent cells in the induction of a primary immune response to sheep erythrocytes in vitro. The results support the hypothesis that there is a functional deficiency of adherent cells in the spleens of unprimed NZB mice.

Animals↗
PubMed1972

Immunological memory in mice. 3. Memory to heterologous erythrocytes in both T cell and B cell populations and requirement for T cells in expression of B cell memory. Evidence using immunoglobulin allotype and mouse alloantigen theta markers with congenic mice.

Using anti-allotype sera and AKR anti thetaC3H sera, a requirement for two cell types has been demonstrated in the adoptive secondary response of mice to heterologous erythrocytes. The cell types have been designated B cells [precursors of plaque-forming cells (PFC)] and T cells (thymus-influenced cells, not providing precursors of detectable PFC). The in vivo indirect PFC response of spleen cells from primed mice is markedly reduced by in vitro treatment of the cells with a mixture of anti-theta serum and guinea pig serum (Anti theta + GPS). This B cell response is fully restored to control levels by thymus cells from normal mice which do not themselves provide precursors of indirect PFC. Thus memory is carried by the B cell lineage but the expression of this memory is dependent on the presence of a cell population which is sensitive to Anti theta + GPS and which is replaced functionally by unprimed T cells. When assayed for T cell activity, thoracic duct cells from specifically primed mice are better than cells from nonspecifically primed mice in restoring the B cell response of spleen cells from immunized mice. Moreover, the T cell activity of a reconstitutive cell population from primed mice is reduced by incubation with Anti theta + GPS. We conclude that memory to heterologous erythrocyte antigens is carried by the T cell lineage as well as the B cell lineage even though unprimed T cells are sufficient for expression of B cell memory.

Animals↗
PubMed1970

Cell interaction in an immune response in vitro: requirement for theta-carrying cells.

Cytotoxic antiserum to theta antigen reduces the capacity of mouse spleen cells to generate direct and indirect plaque-forming cells to sheep erythrocytes in vitro but does not affect plaque-forming cells, their precursors, or hemopoietic stem cells. The response of spleen cells treated with antiserum to theta antigen is restored by thymus cells incubated in vivo with sheep erythrocytes.

Animals↗
PubMed1967

Immunization of dissociated spleen cell cultures from normal mice.

A culture system for cell suspensions from mouse spleens has been described. The system provides adequate conditions for in vitro immunization on initial exposure to heterologous erythrocytes. The in vitro response closely parallels that observed in vivo with respect to size, early kinetics, antigen dose, and the inhibitory effect of passive antibody. The response of cultured cells differs in two respects from that seen in vivo. There is an increase in the ability to discriminate between different varieties of homologous erythrocytes and the in vitro response does not appear to be limited by whatever mechanisms regulate the in vivo response.

Animals↗
PubMed1967

Cell populations and cell proliferation in the in vitro response of normal mouse spleen to heterologous erythrocytes. Analysis by the hot pulse technique.

The role of proliferation in the development of 19S antibody-forming cells in the primary response has been investigated in an in vitro system. Spleen cell suspensions from normal, unimmunized mice were cultured in vitro in the presence of mammalian erythrocytes and the number of 19S hemolytic plaque-forming cells that arose 4 days later was measured. The hot pulse technique for the selective irradiation of those cells which synthesize DNA during a defined period of time has been described. The effect of such hot pulses administered at various times after the addition of antigen on the subsequent appearance of antibody-forming cells was determined. The results established that: (a) the onset of DNA synthesis does not start for approximately 24-32 hr after the addition of antigen, (b) essentially all the antibody-forming cells arise by cell division, and (c) different cell populations are involved in the response to two non-cross-reacting antigens.

Animals↗
PubMed1966

Immunization of normal mouse spleen cell suspensions in vitro.

Dissociated cells from the spleens of unimmunized mice were cultured with and without various mammalian erythrocytes. Spleen cell suspensions cultured with heterologous red cells developed levels of hemolytic plaque-forming cells only one log(2) less than those seen in vivo. The reaction is specific for the in vitro immunizing erythrocytes. Antibody was demonstrated in the culture fluids.

Animals↗