Biomedical subjects
S Faine
Publications and source records attributed to S Faine.
Immunogenicity of boiled compared with formalized leptospiral vaccines in rabbits, hamsters and humans.
Leptospires (Leptospira interrogans serovar pomona) grown in chemically defined medium were immunogenic when given intradermally in humans if the leptospires were killed with formalin but not if they were boiled. Boiled leptospires were immunogenic for rabbits and hamsters and protected hamsters from challenge infection. On the other hand, boiled leptospires of the biflexa complex, serovar patoc, did retain some immunogenicity in humans, but the antisera did not protect hamsters against challenge with serovar pomona.
Detection of specific anti-leptospiral immunoglobulins M and G in human serum by solid-phase enzyme-linked immunosorbent assay.
The enzyme-linked immunosorbent assay (ELISA) was used to detect leptospire-specific immunoglobulin M (IgM) and IgG in the sera of patients infected with leptospiral serovars hardjo, pomona, or copenhageni. All patients produced specific IgM and IgG detectable by ELISA. In contrast, only a few patients produced IgG agglutinins whereas all produced IgM agglutinins. The specificity and sensitivity of the test suggest that the ELISA anti-IgM technique is a suitable method for detecting leptospiral antibodies in human sera for diagnostic and epidemiological purposes.
Comparative studies on two antigens (F4 and TM) extracted from leptospires.
F4 and TM antigens extracted from Leptospira interrogans serovars pomona, icterohaemorrhagiae, and copenhageni were compared by immunodiffusion, by hemagglutination inhibition, and by selective absorption of antisera. These data, together with previous information on the serological specificities of the two antigen preparations, suggest that F4 and TM are different antigens.
Maturation of humoral immune response determines the susceptibility of guinea-pigs to leptospirosis.
Baby guinea-pigs were susceptible to infection with Leptospira interrogans serovar pomona, but rapidly became resistant as they matured. Increased resistance with increasing weight of guinea-pigs was correlated with the development of ability to produce agglutinating antibodies to leptospires and with maturation of B-cell dependent (but not T-cell dependent) areas in lymphoid organs. These observations can explain the basis of species-resistance of adult guinea-pigs to infection with serovar pomona.
Of course it couldn't happen here.
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Rapid presumptive bacteriological diagnosis of Legionnaires disease.
A simple, relatively rapid silver impregnation stain has been found to stain Legionella pneumophila effectively in paraffin-embedded tissue sections while permitting visualization of histological detail. It may also be used to stain the organism in body fluids. The stain is not specific and thus must be confirmed by direct fluorescent-antibody technique or culture, but, in the absence of other bacilli demonstrable by Gram or other stain, visualization of typical bacillary forms in a patient with illness compatible with Legionnaires disease provides strong presumptive evidence supporting this diagnosis.
Serological cross-reactions of leptospiral lipopolysaccharide (F4) antigen.
The serological specificity of leptospiral lipopolysaccharide (F4) antigen was examined by the technique of passive haemagglutination. F4 extracted from leptospiral serovars representative of several different serogroups showed wide cross reaction between serovars, including numerous one-way (non-reciprocal) reactions. The pattern of cross reaction was different to that of the standard leptospiral classification scheme.
Effective protection against influenza after vaccination with subunit vaccine.
Immunization with an influenza subunit vaccine given in one dose about 1 month to 2 months before onset of an epidemic of influenza afforded from 80% to 90% protection in a double-blind clinical trial which was supported by isolation of virus and serological studies. In the vaccinated group, 20% failed to develop antibodies to the vaccine. Either serology tests or attempted isolation of virus alone would have failed to detect some of the cases.
The antibodies involved in the human immune response to leptospiral infection.
Antibody responses were studied in human patients from whom leptospiral serovars--mainly pomona or hardjo--had been isolated and identified. The antibody to the polysaccharide F4 antigen belonged exclusively to the IgM class, even as late as 10 months after infection. Human sera cross-reacted widely with F4 antigen from heterologous serovars. The antibodies involved in leptospiral agglutination were mainly IgM, but some patients also produced IgG agglutinins. The titres of IgM agglutinins were higher than those of IgG agglutinins and persisted for many months, regardless of the presence or absence of IgG agglutinins. Both types of immunoglobulin from patients with serovar pomona infection protected hamsters against lethal infections with homologous leptospires. The hamster-protective capacity of human sera correlated well with agglutinin titres. Sera from patients infected with serovars other than pomona protected hamsters against challenge with pomona only if they contained agglutinins to that organism.
Serological and protective-antibody responses of rabbits to leptospiral antigens.
The rabbit antibody response to leptospiral F4 antigen extracted from serovar pomona depended on the method of immunisation. Intravenous injection of whole leptospires stimulated F4 antibodies that were confined to the IgM class, but leptospires injected intramuscularly with adjuvant stimulated F4 antibodies in both the IgM and the IgM and the IgG classes. Both methods of immunisation stimulated agglutinins in both the IgM and IgG classes. F4 antigen in soluble form was immunogenci when injected intradermally with adjuvant, but not when given alone. The F4 antibodies were distinct from the agglutinins in that they did not protect hamsters from acute infection with homologous leptospires, nor did they kill leptospires in vitro although they reacted with leptospires. The hamster-protective capacity of rabbit sera depended on the level of agglutinin.
The bottom of the antibiotic box.
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Host immunological mechanisms in the resistance of mice to leptospiral infections.
Several serovars of Leptospira virulent for hamsters and guinea pigs caused acute lethal leptospirosis in mice immunosuppressed with cyclophosphamide. Neither BCG vaccine nor Corynebacterium parvum suspension influenced the course of leptospiral infection in either immunosuppressed or normal BALB/c mice. Nude athymic mice produced anti-leptospiral antibody and were therefore resistant to infection with leptospires. Nude mice were made susceptible with cyclophosphamide but were immune if they had acquired antibody from previous infection or immunization. The evidence suggests that mechanisms of resistance to primary infection and immunity to reinfection are exclusively humorally mediated in mice. The roles of host and microbial factors in the outcome of infection are discussed.
Susceptibility of mice treated with cyclophosphamide to lethal infection with Leptospira interrogans Serovar pomona.
Mice not normally susceptible to infection with Leptospira interrogans serovar pomona were rendered susceptible to lethal infections by treatment with a single dose of 300 mg of cyclophosphamide (Cy) per kg administered optimally from 4 days before to 1 day after infection. Cy-treated mice with either passively or actively acquired antibody were protected from death. Blood levels of leptospires in infected untreated and in Cy-treated mice remained similar until 2 days after infection, when untreated mice cleared the leptospires. Soon afterwards, opsonizing and agglutinating antibody appeared. Cy-treated mice given spleen cells from other normal or specifically immune mice were protected from infection. An important factor in the natural resistance of mice to leptospiral infection appears to be their capacity to produce circulating antibody within 48 to 72 h. Applications are suggested for this animal model in vaccination and protection studies.
The sterilization of gutta-percha points.
The traditional methods employed for the sterilization of gutta-percha points are unsatisfactory. The use of propylene oxide for this purpose is described and experimental evidence is advanced to support this use.
A mechanism of immunity to leptospirosis.
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Chemical, serological and biological properties of a serotype-specific polysaccharide antigen in Leptospira.
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Cross-reactivity of the axial filament antigen as a criterion for classification of Leptospira.
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