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Biomedical subjects

A L Notkins

Publications and source records attributed to A L Notkins.

At least 271 records · Page 15Linked to original sources

Iodine-125-labeled antibody to viral antigens: binding to the surface of virus-infected cells.

The specific binding of iodine-125-labeled antibody to viral antigens can be used to detect newly synthesized viral antigens and determine the time of appearance of these antigens on the surface of infected cells. Incubation of infected cells with unlabeled antibody to viral antigens specifically blocks the attachment of labeled antibody, and by this inhibition technique the titer of unlabeled antibody to viral antigens can be calculated. The attachment of the labeled antibody to virus-infected cells offers an objective and sensitive method of detecting viral antigens and measuring antibody to virus.

Animals↗

In vitro stimulation of sensitized lymphocytes by herpes simplex virus and vaccinia virus.

Splenic lymphocytes from rabbits immunized with herpes simplex virus (HSV) were incubated in vitro with ultraviolet light-inactivated HSV, and the degree of lymphocyte transformation was determined by measurement of the incorporation of [(3)H]thymidine into acid-insoluble material. Lymphocytes from immunized rabbits were stimulated as much as 30-fold, whereas lymphocytes from control rabbits were unaffected. Lymphocyte sensitization occurred within 3 days after immunization; sensitized lymphocytes could still be detected 120 days after immunization. The antigenicity of the ultraviolet light-inactivated crude virus pool was found to reside primarily in the virion. Infectious virus, in comparison with inactivated virus, produced less lymphocyte stimulation. Studies on the interaction of the humoral and cellular immune responses showed that incubation of anti-HSV antibody with HSV antigens did not reduce the capacity of the viral antigens to stimulate sensitized lymphocytes. Other experiments revealed that lymphocytes from both the spleen and peripheral blood of animals immunized with vaccinia virus could be stimulated by vaccinia, but not by HSV. Conversely, lymphocytes from animals immunized with HSV could not be stimulated by vaccinia. The transformation of sensitized lymphocytes by viral antigens appears to be a simple, highly specific, and quantitative in vitro technique for the study of the cellular immune response to viral infections.

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Virus-associated immunopathology: animal models and implications for human disease. 1. Effects of viruses on the immune system, immune-complex diseases, and antibody-mediated immunologic injury.

The tissue damage caused by virus infection has been traditionally explained by the ability of viruses to multiply in cells and thereby injure or destroy them. Recent evidence suggests, however, that lesions may also be caused by the host's immune response to viral antigens and that the immune system itself may be perturbed by some viruses. This memorandum reviews recent developments in viral immunopathology, with special reference to animal model systems, and indicates the possible relevance of the new concepts and techniques for certain diseases of man. Certain viruses, notably the leukaemia viruses and some of those causing persistent infections, depress the host's ability to mount an antibody response to antigens, while other viruses may enhance the antibody response. Cell-mediated immunity may also be depressed. Another immunopathological manifestation of virus infection is immune-complex disease. When viruses or their antigens persist in the circulation they combine with specific antibody, and the resulting complexes lodge in various sites, especially the kidney. Further combination with complement leads to the release of tissue-damaging substances. A third condition associated with virus infection is antibody-mediated immunologic injury. Both oncogenic and non-oncogenic viruses frequently induce new antigens on the surface of the cells they invade. When antibody attaches to these antigens in the presence of complement, the cells are destroyed.

Animals↗

Virus-associated immunopathology: animal models and implications for human disease. 2. Cell-mediated immunity, autoimmune diseases, genetics, and implications for clinical research.

Part 2 of this memorandum describes further mechanisms whereby the interaction of a virus with the host's immune system may lead to tissue damage. Cell-mediated immunity plays a vital role in promoting recovery from virus infections, but under some circumstances tissue damage may be caused by the reaction of immune cells with viral antigens. When mice are infected with lymphocytic choriomeningitis virus neonatally or as adults while receiving immunosuppressive drugs, widespread invasion of cells is seen but there is little overt disease. If, however, normal adults are infected or if immune cells are transfused into tolerant mice, cell injury and death follow. Viruses have long been suspected of contributing to the pathogenesis of autoimmune diseases. Antibodies directed against normal cell constituents have been reported in several virus infections. Viruses may conceivably unmask or release host antigens, alter host antigens and act as "helper determinants", or perhaps in other ways provoke immune responses against normal body constituents. The immunopathological manifestations caused by viruses may also be influenced by the host's genetic makeup. Certain observations indicate that, in addition to controlling susceptibility to virus infection, genetic factors partly determine the effectiveness of the immune response. The memorandum calls attention to the possible implications of these concepts and findings for clinical research. Some of the diseases of animals and man that serve as models for studies of virus-associated immunopathology are briefly described.

Anemia↗

Interaction of rheumatoid factor with infectious herpes simplex virus-antibody complexes.

Rheumatoid factor, a human immunoglobulin of the IgM class, failed to attach to herpes simplex virus but did attach to infectious complexes composed of herpes simplex virus and antibody to herpes simplex virus. These newly formed complexes of infectious virus, antiviral antibody, and rheumatoid factor could be neutralized by complement or by antibody to human IgM. The ability of rheumatoid factor to enhance virus neutralization in the presence of complement represents a hitherto unrecognized biological role for rheumatoid factor.

Animals↗

Inhibition or enhancement of immunological injury of virus-infected cells.

Within hours after infection of cells with herpes simplex, vaccinia, influenza, or Newcastle disease virus, new antigens appeared on the surface of infected cells. The interaction of specific antiviral antibody and complement with these antigens resulted in cell destruction, which was quantitated by the release of (51)Cr. A number of factors can influence the degree of cell destruction, including the density of viral antigens on the surface of infected cells, the nature of the antiviral antibody, and the presence of anti-immunoglobulins. The immunological destruction of virus-infected cells may on the one hand serve as a defense mechanism against certain viral infections, while on the other hand it may contribute to the pathology of the host.

Animals↗

Inflammation and herpes simplex virus: release of a chemotaxis-generating factor from infected cells.

Infection of primary rabbit kidney cells with herpes simplex virus leads to the release of a cell factor or factors that upon incubation with serum results in the cleavage of the fifth component, C5, of complement. The product of this cleavage, C5a, is chemotactic for polymorphonuclear leukocytes and could be responsible for the accumulation of these cells at the site of herpetic lesions.

Animals↗

Neutralization of sensitized virus by purified components of complement.

Herpes simplex virus which had been sensitized with immunoglobulin M antibody was neutralized by serum deficient in the fifth and sixth components of complement (C) but not by serum deficient in the fourth component C (C4). The sequential addition of the functionally purified components of C showed that the activated first component of C (C1[unk]) failed to neutralize sensitized virus. However, in the presence of an optimal concentration of C1[unk], the addition of C4 resulted in neutralization. The amount of virus neutralized was dependent upon the concentration of immunoglobulin M used to sensitize the virus and the concentration of C1[unk] and C4. The addition of the second component of C (C2) to reaction mixtures containing an optimal concentration of C1[unk] and a limiting concentration of C4 resulted in increased neutralization and the amount of virus neutralized was dependent upon the concentration of C2. The addition of the third component of C (C3) to reaction mixtures containing an optimal concentration of C1[unk] and limiting concentrations of C4 and C2 also resulted in increased neutralization and the amount of virus neutralized was dependent upon the concentration of C3.

Animals↗

Neutralization of sensitized virus by the fourth component of complement.

Herpes simplex virus which had been sensitized with IgM antibody was not neutralized by the addition of the purified activated first component of complement. In the presence of an optimum concentration of the first component of complement, however, the sensitized virus was neutralized by the addition of a high concentration of the purified fourth component of complement. Under these conditions, the addition of the purified second and third components of complement failed to enhance virus neutralization. With low concentrations of the fourth component of complement, the addition of the second and third components enhanced virus neutralization.

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