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C Michie

Publications and source records attributed to C Michie.

26 records · Page 2Linked to original sources
PubMed1994

Can expression of CD45RO, a T-cell surface molecule, be used to detect congenital infection?

Exclusion or confirmation of congenital infection can be difficult in newborn infants. The presence of an infective organism in a fetus leads to activation of fetal T lymphocytes. We have examined expression of isoforms of a T-cell surface molecule, CD45RO, in 119 infants, 8 of whom had an intrauterine infection diagnosed antenatally. CD45RO was expressed on fewer than 10% of T cells in control infants and on more than 17% of T cells from infants with known infection (p < 0.006). This method allows screening of infants for infection by a range of organisms as a cause of their infection.

Female↗
PubMed1994

Streptococcal toxic shock-like syndrome: evidence of superantigen activity and its effects on T lymphocyte subsets in vivo.

Toxic shock-like syndrome is a serious complication of invasive streptococcal disease. The syndrome is believed to be the consequence of exposure to exotoxins produced by the infecting organisms which behave as superantigens. We describe two patients who fulfilled clinical criteria for this syndrome, one of whom died. Streptococci isolated from both patients were found to produce a mitogen specific for the V beta 2+ T lymphocyte subset in vitro, which had the characteristics of a superantigen. The phenotype and function of lymphocytes collected from both patients during the acute phase of their illness demonstrated a marked reduction in circulating CD4+ ('helper') and CD45RA+ ('naive') T lymphocytes expressing the V beta 2 chain, and an increase of those expressing CD8, CD45RO and the V beta 2 chain. This effect resolved within 4 weeks in the patient who survived. Proliferation assays demonstrated no T cell anergy in either patient. Stimulation of lymphocytes by superantigen in these clinical situations does not appear to cause permanent deletion of T cell subsets, as has been observed in animal models.

CD4-Positive T-Lymphocytes↗
PubMed1993

Viral burden in AIDS.

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Acquired Immunodeficiency Syndrome↗
PubMed1991

T cell responses to peptides covering the gag p24 region of HIV-1 occur in HIV-1 seronegative individuals.

We demonstrate that peptides (16 amino acids long) covering the sequence of the HIV-1 core protein p24 induce significant proliferation in peripheral blood mononuclear cells (PBMC) of several (greater than 50%) healthy seronegative volunteers as well as seronegative homosexual men. The nature of this response was characterized and compared with those of HIV-infected patients. Several peptides induced responses; however, the most frequent responses in both seropositive and seronegative individuals were noted to the following peptides: 1 and 2 (aa 133-157); 6 and 7 (aa 183-207); 15 (aa 273-287); and 17 and 18 (aa 293-317). The response pattern was related to the disease stage of the patients; seronegative individuals as well as asymptomatic seropositive individuals (CDC II/III) responded to low concentrations of several peptides, but symptomatic patients (CDC IV) only responded to high concentrations of a few peptides. Cell separation studies of PBMC from healthy volunteers showed that the responding cells were CD4+ and expressed the CD45RO differentiation antigen. Furthermore, cord-blood mononuclear cells with less than 5% of CD45RO T cells did not proliferative to any of the peptides. Finally, CD4+ T cell lines specific for both peptides and p24 protein were successfully established from the PBMC of seronegative individuals confirming the data obtained with freshly isolated cells. These studies therefore suggest that the CD4+ cell response to p24 is not strictly disease related, instead, the response may be due to priming of the host with cross-reactive antigens.

Amino Acid Sequence↗