PubMed Health⌕ Search

Biomedical subjects

A M SILVERSTEIN

Publications and source records attributed to A M SILVERSTEIN.

At least 19 recordsLinked to original sources
PubMed1964

FETAL RESPONSE TO ANTIGENIC STIMULUS. IV. REJECTION OF SKIN HOMOGRAFTS BY THE FETAL LAMB.

The fetal lamb was found to reject orthotopic skin homografts applied at any time after the 77th day of gestation. Prior to this, grafts remained in place without stimulating any detectable immunologic response. Once the fetus achieves the ability to reject the graft, the process occurs with the same competence and rapidity as in the adult. Graft rejection in the fetal lamb is unaccompanied by formation of plasma cells or by the production of typical immunoglobulins, thus supporting the suggestion that circulating antibody does not play an obligatory role in the process.

Allografts↗
PubMed1963

HOMOGRAFT REJECTION IN THE FETAL LAMB: THE ROLE OF CIRCULATING ANTIBODY.

Specific rejection of sterile orthotopic skin homografts by the fetal lamb in utero was unaccompanied by the presence of plasma cells in either the graft and its bed, or in the reactive draining lymph node. The grafts appeared not to stimulate the production of circulating immunoglobulins. The presence in the fetal circulation of rabbit anti-sheep 7S gamma-globulin and anti-beta(2M)-globulin did not inhibit the normal course of homograft rejection. These data support the contention that conventional circulating antibody is not an obligatory participant in the rejection of solid-tissue homografts.

Allergy and Immunology↗
PubMed1963

Fetal response to antigenic stimulus. II. Antibody production by the fetal lamb.

The fetal lamb in utero is able to form large amounts of specific antibody in response to antigenic stimulus as early as the 66th to 70th day of the 150 day gestation period. Among the several antigens employed, the fetal lamb responded earliest, and with the highest titers, to bacteriophage varphiX. Slightly less effective as an antigen was horse ferritin, while ovalbumin proved to be a weak antigen, especially in younger fetuses. Ineffective in stimulating an antibody response at any time during fetal or early neonatal life were diphtheria toxoid, Salmonella typhosa, and BCG. Thus, it may not be feasible to fix precisely the time of onset of immunologic responsiveness in a species, inasmuch as it appears to differ so greatly from one antigen to another. The quantity of antibody found 10 days after varphiX immunization was not significantly different in fetuses injected at 60 to 120 days of gestation. The earliest anti-phage antibody produced by the lamb fetus is a macroglobulin sensitive to the action of 2-mercaptoethanol. Only in older fetuses with longer lasting stimuli were appreciable amounts of 7S gamma-globulin antibodies formed. The conformity of these observations to theories on the ontogenesis of the immune response is discussed.

Amphotericin B↗
PubMed1962

Delayed hypersensitivity to hapten-protein conjugates. I. The effect of carrier protein and site of attachment to hapten.

Further data have been presented showing that the specificity of the delayed hypersensitivity reaction in the guinea pig to hapten-protein conjugates involves to a considerable degree a contribution by the protein carrier. The carrier contribution is such that sensitization to guinea pig albumin-m-azobenzenesulfonate, for example, does not result in cross-reaction with conjugates of the same hapten with unrelated proteins such as ovalbumin or human gamma globulin, nor were cross-reactions observed between conjugates prepared with the same hapten, coupled to the same protein, but by two different chemical routes, such that the point of attachment of the hapten to the protein differed. It thus appears that in this system both hapten and carrier protein are necessary, but that neither alone is in general sufficient to stimulate the delayed sensitive cell. Desensitization experiments with cross-reacting hapten-protein conjugates have suggested the presence of a multiplicity of antigenic determinants participating in the elicitation of the delayed lesion, and of a concomitant development of a heterogeneity of specificities in the population of delayed sensitive cells in the sensitized animal. The data are discussed in terms of the apparent requirement of the delayed sensitivity mechanism for a larger functional antigenic determinant than that required for interaction with circulating antibodies. Some possible explanations for this difference, and some of its consequences, are discussed.

Animals↗
PubMed1962

Delayed hypersensitivity to hapten-protein conjugates. II. Anti-hapten specificity and the heterogeneity of the delayed response.

The cross-reactions of conjugates carrying structurally related haptens have been studied in guinea pigs with delayed sensitivity to hapten-protein conjugates. The specificity of the delayed reaction has been found to be a function both of the nature and of the position of the substituent on the benzene ring; the cross-reactions shown in the delayed system, however, have been found to be appreciably more extensive than those reported for rabbit antibody systems employing identical haptens. This finding supports the earlier suggestion that the determinant in the delayed system is functionally larger than that required for reaction of antigen with conventional antibody. Desensitization studies with cross-reacting antigens have indicated that the delayed hypersensitivity response is characterized by the production of a heterogeneous population of cells, all more or less closely adapted to the structure of the homologous hapten conjugate.

Animals↗