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Biomedical subjects

A M Silverstein

Publications and source records attributed to A M Silverstein.

At least 91 records · Page 5Linked to original sources
PubMed1979

Secretory immune system of rabbit ocular adnexa.

A distinct system of immunity in a variety of animals is located subjacent to epithelial surfaces and is typified by the predominance of immunoglobulin A (IgA) and secretory component (SC) in various external secretions, including tears. The present study examined normal rabbit lacrimal gland, conjunctiva, and cornea for the presence of immunoglobulin and SC. IgA-staining plasma cells predominated within lacrimal gland and conjunctival stroma, and SC was found in the epithelial cells of both these tissues but not within corneal epithelium. These observations are consistent with findings for other secretory sites in both rabbits and humans and establish lacrimal gland and conjunctiva as integral parts of the rabbit secretory immune system.

Animals↗
PubMed1978

Nonspecific signals for B-cell localization and activation.

Virgin, inactive mammary gland autografted to the anterior chamber of the rabbit eye remains free of lymphoid cells. Activation of the ectopic gland by systemic injection of chorionic gonadotropin results in maturation of the gland and milk production, accompanied by the immirgration of lymphocytes and their activati-n to Ig formation, predominantly of the IgA class. In the presence of antigen-induced intraocular inflammation, the activated gland is able to influence the Ig class of B cells in the neighboring ocular tissues. These data suggest that even nonlymphoid tissues may elaborate lymphocyte-homing and polyclonal B-cell activating factors which function independently of specific antigen.

Animals↗
PubMed1977

Slow virus infection: replication and mechanisms of persistence of visna virus in sheep.

The influence of the age and immune status of the host on the slow replication and persistence of visna virus in sheep was studied. Twenty-five randomly bred fetal American lambs were inoculated intracerebrally with visna virus. Eight of these fetuses were immunosuppressed by thymectomy and antiserum to lymphocytes before inoculation. Fetuses were sacrificed sequentially, and tissues were processed for viral quantitation. No exponential increase of virus occurred in either the normal or immunosuppressed fetuses, and virus was recovered mainly by explanation of tissues. This finding indicated that the viral genome was present in tissue cells but that the extent of replication in the early phase of infection was restricted by factors unassociated with maturation or immune status of the host. In addition, virus isolated from the peripheral blood leukocytes of a sheep one year after inoculation was antigenically distinct from the plaque-purified virus used for inoculation. This distinction suggested that a major antigenic shift of the agent had occurred and provided another mechanism for the maintenance of the persistent infection.

Animals↗
PubMed1976

Lymphocytic choriomeningitis virus-induced ocular immunopathology.

Lymphocytic choriomeningitis (LCM) virus of the mice provides perhaps the most extensively studied model of viral-induced immunopathology. Intraocular inoculation of this virus in the adult mouse produces a severe and progressive uveitis with involvement also of the cornea and retina. Intracerebral infection of the newborn rat with LCM virus produces a severe retinopathy, with only minimal involvement of the uveal tract. We review in this paper recent studies on these two animal models of LCM virus disease which demonstrate: (1) the histopathology of the ocular lesion; (2) that immunosuppression after infection prevents development of the disease; (3) that passive transfer of sensitized lymphoid cells to the immunosuppressed infected animal can then trigger ocular disease, and (4) that T lymphocytes, and not circulating antibody, play the major role in the pathogenesis of this disease process.

Animals↗
PubMed1976

Induction of corneal graft rejection by passive cell transfer.

An experimental model is presented demonstrating that penetrating corneal grafts in the rabbit may be rejected by passive transfer into the anterior chamber of specifically sensitized lymphoid cells. Destruction of histo-incompatible corneal endothelium is always marked by the formation of focal pock-like areas of damage in this system, rather than by the typical moving line of rejecting endothelium usually seen in spontaneous graft rejection. Where the transferred lymphoid cells are compatible with the tissues of the graft recipient, the picture is one of a severely affected graft on a field of uninvolved recipient corneal endothelium. Where the lymphoid cells are compatible with the graft and not with the tissues of the recipient, one sees a clear corneal graft surviving on a field of endothelial destruction on the recipient bed. The specificity of these reactions is illustrated in terms of the histocompatibility relationships between corneal donor, graft recipient, and the donor of the sensitized lymphoid cells.

Animals↗
PubMed1975

The ontogeny of antigen-specific T cells.

Although the fetal lamb is unable to form circulating antiovalbumin antibodies until about 120 days of gestation, ovalbumin-specific helper T cells can be stimulated to function at an earlier age. This would suggest that the critical event responsible for the precise sequential maturation of immunologic competence to different antigens at different developmental stages is not the first appearance of specific receptors on immunocytes. Alternative explanations of this phenomenon are discussed.

Animals↗
PubMed1975

Local antibody formation within the eye: a study of immunoglobulin class and antibody specificity.

Primary immunogenic uveitis was induced in the rabbit eye with a single injection of antigen into the vitreous, and secondary booster uveitis responses were induced two months later by intravenous administration of the same antigen. The distribution of immunoglobulin classes and the specificity of the antibodies produced were assessed early and late in the primary response and early and late in the secondary response, and were compared with the analogous responses in the spleen and regional lymph nodes. At each of these stages of intraocular antibody response, IgG formation was higher and IgM formation lower than that seen in organized lymphoid tissues, while the proportion of IgA-forming cells was similar to the low levels usually found in the spleen. A significant proportion of IgA-forming cells was found in the perilimbal conjunctiva, and even greater levels in the lacrimal glands. At each stage of the response, the proportion of immunoglobulin-forming cells making antibody specific for the inciting ovalbumin antigen was surprisingly low, reaching only seven per cent during the late primary reaction and 18 per cent during the late secondary reaction.

Animals↗
PubMed1975

Local graft versus host reactions within the anterior chamber of the eye: the formation of corneal endothelial pocks.

Introduction into the rabbit's anterior chamber of lymphoid cells sensitized to the histocompatibility antigens of the recipient leads to the development of an intraocular graft versus host reaction. This takes the form of a more-or-less severe uveitis, and the production of small focal areas of endothelial cell destruction on the posterior surface of the cornea. In the milder responses, these present as discrete pocks on the endothelial layer, which heal rapidly. In the more severe reactions, the foci of endothelial destruction may be so numerous as to overlap, resulting in complete immunologic destruction of the entire endothelium. The dose-response relationships in this experimental system are discussed, as are its uses as a model for the study of the mechanism of endothelial damage during the course of specific corneal graft rejection.

Animals↗
PubMed1974

Visna virus infection of American lambs.

Random-bred fetal and 4-week-old American lambs, inoculated intracerebrally with visna virus, developed a persistent infection in the brain and sometimes in the lung. The pathologic changes present in these lambs were similar to the early lesions of visna in Icelandic sheep, thus providing a possible model for the study of virus-induced demyelinating disease.

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