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Biomedical subjects

T Vesikari

Publications and source records attributed to T Vesikari.

At least 145 records · Page 8Linked to original sources
PubMed1978

In vitro invasiveness of Yersinia enterocolitica isolated from children with diarrhea.

The invasiveness of Yersinia enterocolitica isolated from the feces of children with diarrhea was assayed in cultured human epithelial (HEp-2) cells. Twenty-one of 24 strains were invasive under the test conditions. Infection with Y. enterocolitica was characterized clinically by exudative diarrhea in 11 cases. Polymorphonuclear leukocytes were demonstrated in the feces from all three cases of exudative diarrhea studied. The results suggest a correlation between enteroinvasiveness of Y. enterocolitica, presence of leukocytes in feces, and clinical exudative diarrhea.

Adolescent↗
PubMed1976

Study of the lymphocyte in vitro response to rubella antigen and phytohemagglutinin by a whole blood method.

A whole blood culture method was used to study lymphocyte in vitro responses to rubella antigen and to phytohemagglutinin (PHA) in rubella infection. The acute phase of infection in four cases was characterized by high spontaneous incorporation of 14C-thymidine in the cultures, unresponsiveness of lymphocytes to rubella antigen, and absence of response, or relatively low response, to PHA. Cells showing vigorous in vitro response to rubella antigen appeared at about two weeks after the onset of rash. Lymphocyte PHA response returned to normal by day 31. Three rubella vaccinees exhibited a similar response. The use of whole blood lymphocyte cultures stimulated with multiple doses of mitogen and with antigen appears to be a promising technique for studies of "general" and "specific" cell-mediated immunity in viral infections.

Adult↗
PubMed1975

Lymphocyte responses to rubella antigen and phytohemagglutinin after administration of the RA 27/3 strain of live attenuated rubella vaccine.

Lymphocyte phytohemagglutinin (PHA) responsiveness was found suppressed in both rubella sero-negative and sero-positive recipients of RA 27/3 strain of live attenuated rubella vaccine; the suppression was readily demonstrable only when a suboptimal dose of PHA was applied in the test. Lymphocytes from sero-negative vaccinees, which initially showed little or no in vitro response to concentrated rubella virus, became responsive after vaccination by day 21, when the highest sensitization to rubella antigen was seen. In the sero-positive vaccinees. lymphocytes responded to rubella antigen in vitro before vaccination, and in most cases vaccination did not result in significant changes in lymphocyte response. These results suggest that rubella vaccination leads to temporarily increased lymphocyte reactivity to rubella antigen, and the increased lymphocyte response to specific antigen may occur at the time of mild suppression of PHA response.

Adult↗
PubMed1975

Cell-mediated immunity in rubella assayed by cytotoxicity of supernatants from rubella virus-stimulated human lymphocyte cultures.

Rubella virus-stimulated lymphocytes from rubella-seropositive donors produced in the culture medium cytotoxic activity with preferential action against rubella-infected over uninfected target cells. The ability of lymphocytes to produce the cytotoxic activity upon stimulation by rubella virus correlated with the humoral rubella-immunity status, i.e. no such cytotoxic activity developed in the supernatants of lymphocyte cultures of rubella-seronegative donors. Stimulation of lymphocytes from seropositive donors by rubella virus was also detected by thymidine incorporation, but the correlation of lymphocyte responsiveness to the humoral rubella antibody status was not so clear as in the cytotoxicity assay. Conversion of lymphocytes from unresponsive to responsive to rubella virus following natural rubella infection and after rubella vaccination was demonstrated using both methods. Following vaccination rubella-specific cell-mediated immunity first became demonstrable at 14 days. The responsiveness of lymphocytes to phytohaemagglutinin (PHA) after rubella vaccination was followed by studying thymidine uptake and the ability of lymphocytes to produce lymphootoxin. By both tests marked suppression of PHA response occurred at days 3 and 7 after vaccination.

Adult↗
PubMed1975

Cytotoxic activity against rubella-infected cells in the supernatants of human lymphocyte cultures stimulated by rubella virus.

Supernatant fluids of lymphocyte cultures from rubella-seropositive donors, stimulated with inactivated rubella virus, showed cytotoxic activity against rubella-infected target cells (NYU 32 line of human embryonic fibroblasts) but not against uninfected fibroblasts. The time of appearance of cytotoxic activity in rubella-stimulated lymphocyte cultures correlated with increased rate of DNA synthesis as measured by thymidine uptake. No such cytotoxic activity became detectable in the supernatants of lymphocyte cultures from rubella-seronegative donors cultured in the presence of rubella virus, or in unstimulated lymphocyte cultures from seropositive or seronegative donors. The cytotoxic activity was lost at 60degreesC in 30 min. In contrast to this rubella virus-induced cytotoxic activity, cytotoxin produced in mitogen-stimulated lymphocyte cultures from rubella seropositive and seronegative donors was equally cytocidal against rubella-infected and uninfected human fibroblasts. Although the nature of cytotoxic activity remains to be characterized, it is suggested that it is associated with a lymphokine released immune-specifically from rubella virus-stimulated lymphocytes.

Antibodies, Viral↗