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Biomedical subjects

J H Playfair

Publications and source records attributed to J H Playfair.

At least 127 records · Page 7Linked to original sources
PubMed1977

Reactivity and crossreactivity of mouse helper T cells to malaria parasites.

The mouse helper T-cell response to four plasmodial and babesial parasites was measured by using them as carriers for a standard hapten (TNP). Helper T cells appeared to recognize all the parasites, but not to be able to distinguish between them. Helper T-cell responses could be augmented by vaccination with formalin-fixed parasites. However vaccination did not always confer protection against infection. Conversely, mice resistant to infection because of prior recovery from a homologous or heterologous infection had normal or reduced helper T-cell responses. It is concluded that resistance to infection with these parasites, though dependent on T cells, may not only involve the helper T-cell subpopulation.

Animals↗
PubMed1977

Protection of mice against malaria by a killed vaccine: differences in effectiveness against P. yoelii and P. berghei.

(C57BI x Balb/c)F1 mice are normally killed by a strain of the malaria P. yoelii, but they can be fully protected by a killed vaccine. The best results were obtained with saponin-lysed parasitized cells subsequently fixed with 0-06% formalin and injected intravenously with the adjuvant B. pertussis, though good protection was also obtained without the adjuvant. The protection was specific and at least partly mediated by a serum factor. A similar regime gives little or no protection against P. berghei. Possible reasons for this difference are considered and the mechanisms by which vaccination works against P. yoelii are discussed.

Animals↗
PubMed1977

Hyper-responsiveness in NZB mice to the experimental induction of anti-red cell autoantibody.

Strain differences in ease of induction of autoantibody production were observed when mice were injected with rat RBC. Responsiveness was not linked to the H-2 locus. NZB and (NZB X BALB/c)F1 mice were hyper-responsive both in terms of the induction of autoantibody and in the production of agglutinating antibody to rat RBC. C57BL/c and (C57BL X BALB/c)F1 were poor responders. Injection of the rat RBC in FCA converted a poor responder into a good responder. Adult thymectomy and ALS treatment did not significantly enhance autoantibody production.

Animals↗
PubMed1975

C3 receptor. A marker of a thymus-dependent B-cell subpopulation.

Depletion of C3-binding cells from spleen virtually abolishes the T cell-dependent response to sheep erythrocytes as assessed by transfer experiments. It is suggested that a functionally thymus-dependent B-cell subpopulation (B2) can be distinguished by surface receptors for C3.

Animals↗
PubMed1975

Age-dependent changes in the relative affinity of anti-dinitrophenyl antibodies in mice.

The affinity of anti-DNP antibodies produced by mice of various ages has been studied at the cellular level by the plaque inhibition technique. The affinity of PFC produced shortly after a single injection of antigen was found to increase during the first 6 weeks of life. The responses of 1- and 2-week-old animals also showed apparently restricted heterogeneity. The difference in the affinity of anti-DNP--PFC between young and adult mice could not be attributed to different (serum) levels of antigen or to differences in the rate of maturation of affinity during the immune response. Cell transfer experiments suggested that the age-dependent increase was due to a change in the population of antibody-forming (B) cell precursors and not to a progressive improvement of T-cell function. This findings is interpreted as favouring somatic mutation theories of antibody diversity.

Age Factors↗
PubMed1975

Rosette formation by mouse lymphocytes. IV. Fc and C3 receptors occurring together and separately on T cells and other leucocytes.

A method is described for detecting the simultaneous presence of Fc and C3 receptors on mouse spleen cells. A proportion of both T cells and non-T cells bear both receptors. Both T-cell and non-T-cell Fc receptors were blocked by aggregated mouse IgG2 to the same degree. C3, but not Fc, receptors were blocked by factors present in the serum of irradiated mice or mice undergoing graft-versus-host reaction. Thymocytes activated by injection into irradiated F1 hybrid mice, and thymocytes regenerating after irradiation and bone marrow injection, appeared to have increased Fc receptors. A general role for Fc and C3 receptors in T cell-B cell co-operation is suggested.

Animals↗