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Biomedical subjects

J D Naysmith

Publications and source records attributed to J D Naysmith.

14 recordsLinked to original sources

IgE antibodies to D. pteronyssinus in atopic patients.

An aqueous house dust mite extract was separated by SDS-PAGE and transferred to nitrocellulose membranes by Western Blotting. Two major allergens, Der pI and Der pII associated with the mite faeces and body, respectively, were identified on the protein blot. The blot was then probed with atopic sera and the bound antibodies were labelled with 125I anti-IgE and visualized by autoradiography. Using this technique it is shown that serum samples from eczema patients contain a higher proportion of anti-mite body IgE antibodies, whereas those from asthma patients contain a higher proportion of antibodies against the major mite faecal allergen Der pI. Minor mite body allergens are also shown to be important in eczematous patients. The role of mite allergens in atopic conditions is discussed, along with the significance of the findings presented here.

Allergens

Comparison of the immunogenic effects of covalent-bonded immune complexes in mice and sheep.

Covalent antigen-antibody complexes containing the protein antigen ovo-transferrin primed both mice and sheep to give an enhanced antibody response to a subsequent single injection of soluble ovo-transferrin. Complexes prepared using horse, sheep or rabbit antibody had a priming effect in mice, although rabbit antibody-antigen complexes were the most effective. In sheep, only rabbit antibody-antigen complexes significantly enhanced antibody levels.

Adjuvants, Immunologic

Anti-erythrocyte autoantibody production in mice associated with the injection of rat erythrocytes.

Mice injected with rat erythrocytes developed anti-erythrocyte autoantibodies which reached a plateau at 4-12 weeks, then gradually declined until at about 24 weeks the majority of mice were negative. In such recovered mice re-challenge with rat erythrocytes produced an accelerated peak of autoantibody and a much more rapid return to a Coombs' negative state. The auto-antibody response was distinguished from the anti-rat response in being more radio-sensitive. Purified autoantibody reacted to higher titre with rat than with syngeneic erythrocytes. Lymphoid cells, from mice given rat erythrocytes (but not sheep, rabbit or guinea-pig erythrocytes) transferred to normal syngeneic recipients given rat erythrocytes suppressed autoantibody production in the recipients. This suppression was much more effective against the autoantibody response than against the response to the inducing cross-reactive antigen; and the degree of suppression was related to the number of cells transferred and to their time of administration relative to the injection of rat erythrocytes. The induction of autoantibody and the generation of suppressor cells in donor animals was unaffected by adult thymectomy. A comparison of the effect of anti-rat erythrocyte antibodies and spleen cells from rat-immunized donors on recipients responses to rat erythrocytes revealed that whereas anti-rat antibodies suppressed both the autoantibody and the anti-rat responses, the spleen cells suppressed only the autoantibody response. Populations of spleen cells, from rat immunized donors, depleted of B cells retained their suppressive activity, whereas the suppressive efficacy of T-cell depleted populations was reduced but not abolished. It is suggested that T cells can specifically interfere with thesponse of autoreactive B cells, although non-T cells (possibly B cells acting by an antibody-feedback mechanism) can also suppress their response.

Animals

A comparison of four methods for measuring cutaneous delayed- type hypersensitivity reactions to protein antigens in the mouse.

Delayed-type hypersensitivity was induced in mice by injecting keyhole limpet haemocyanin or human serum albumin in Freund's complete adjuvant. Four techniques for assessing specific skin reactions in these immunized animals were compared: increase in thickness of the footpad; increase in thickness of the ear; arrival of 51Cr-labelled syngeneic lymph node cells at the challenge site in the ear; and accumulation of (125I)IUdR at the challenge site in the ear. The most sensitive and reliable test for detecting strong and weak reactions proved to be measurement of antigen-induced thickening in the ear.

Animals

Naturally occurring double-stranded RNA and immune responses. Effects on plaque-forming cells and antibody formation.

A highly purified preparation of double-stranded RNA, obtained from virus-like particles in Penicillium cultures, was found to affert humoral immune responses in mice differentially depending on its time of administration in realtion to antigen. Double-stranded RNA administered with antigen, or a few hours after antigen, produced a variable degree of enhancement of plaque-forming cell numbers or agglutinating antibody levels depending on the antigen involved. Administration of double-stranded RNA 24 hours before antigen invariably produced a suppressed response. In mice which were either specifically hyporesponsive (tolerant) or non-specifically hyporesponsive (due to age or immunosuppressive drugs) double-stranded RNA administered with antigen resulted in a nearly normal immune response.

Agglutination Tests

Naturally occurring double-stranded RNA and immune responses. III. Immunogenicity and antigenicity in animals.

Naturally occurring, double-stranded RNA (ds-RNA)) was immunogenic when injected into mice, rats, guinea-pigs, rabbits, dogs and baboons. The response to native material administered intravenously (i.v.) was strongest in rabbits and mice, and weakest in baboons. Mice, guinea-pigs and baboons injected with ds-RNA complexed with methylated BSA emulsified in Freund's complete adjuvant all gave high antibody responses. When ds-RNA was given in aerosol form to mice and guinea-pigs the response was weaker than that following i.v. injection, and baboons did not respond to antigen given as an aerosol. In most species the immune response obtained was predominantly IgM in nature, and there was no evidence for cell-mediated immunity in any species. The only evidence of an adverse reaction associated with repeated administration of ds-RNA was a systemic anaphylactic-type response in a small group of mice given ds-RNA repeatedly in aerosol form and challenged with ds-RNA i.v.

Aerosols