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Biomedical subjects

P K Lai

Publications and source records attributed to P K Lai.

8 recordsLinked to original sources
PubMed1977

Epstein-Barr herpesvirus infection: inhibition by immunologically induced mediators with interferon-like properties.

When sensitized leukocytes were re-exposed to EBV antigen or to tuberculin-purified protein derivatives, they produced lymphokines, including the migration inhibition factor, which inhibited the migration of guinea-pig peritoneal exudate cells, and other lymphokines with the characteristics of interferon, which inhibited EBV-induced transformation and EBV superinfection of target cells. Unsensitized leucocytes from sero-negative adults and from neonates did not produce lymphokines when challenged with the antigens. This indicates that cell-mediated immunity and its associated soluble mediators may be involved in the control of EBV infection and that the interferon release assay is a useful in vitro correlate for the study of cellular immunity to EBV.

Antibodies, Viral↗
PubMed1977

Infectious mononucleosis: recognition and management.

Differentiation from other common viral infections depends on a triad of clinical, hematologic, and serologic determinations. A distinctive feature is that while a number of circulating immunoglobulins are often detected, only Paul-Bunnell antibodies, found in 75% of cases, are specific for IM. Symptomatic care only is indicated for most patients, though severe cases or complications may require antibiotics or corticosteroids.

Adolescent↗
PubMed1977

Development of cell-mediated immunity to Epstein-Barr herpesvirus in infectious mononucleosis as shown by leukocyte migration inhibition.

Eight patients with infectious mononucleosis, aged between 8 and 24, were studied for cell-mediated immunity by the in vitro leukocyte migration inhibition test at acute and convalescent stages. Follow-up studies were also carried out at up to 4 months after clinical illness. Cell-mediated immunity to Epstein-Barr virus (EBV) in the peripheral leukocytes from these patients was absent or incipient in all cases during the acute phase, although it was present in lymphocytes from a biopsied lymph node obtained from one of the patients. In contrast, cell-mediated immunity to EBV was detected readily in peripheral leukocytes obtained during convalescence and in the follow-up studies. A blocking factor that abrogated leukocyte migration inhibition induced by EBV antigen was detected in acute and convalescent sera obtained from six of eight patients, whereas serum antinuclear autoantibodies were detected in the two patients whose sera failed to block leukocyte migration inhibition. When sera were fractionated, this blocking effect was observed only in the serum immunoglobulin G fractions. In follow-up studies, neither the blocking factor nor the antinuclear autoantibodies were found in the sera collected.

Adolescent↗
PubMed1975

Epidemiological studies of Epstein-Barr herpesvirus infection in Western Australia.

In a study of a Caucasian population in Western Australia the prevalence of antibodies to Epstein-Barr virus (EBV) was 41% in the 9- to 10-year age group, 80% in the 16 to 19-year age group and 92% in young adults. The age-specific annual seroconversion rates indicated two peaks of primary EBV infection in the population studied - one under 5 years of age and the other at adolescence. The geometric mean titre rose with age, from 23 at 5-6 years to 53 at 36-40 years. It was shown that in 73 families studied there was evidence of probable spread of EBV infection among siblings, particularly between those of the same sex. Serological study of patients with infectious mononucleosis indicated that 100% of those examined had antibody to EBV and the geometric mean titre was elevated to 210. Rising titres and seroconversion was demonstrated in these patients together with successful establishment of EBV-carrying cell lines from the peripheral blood in two-thirds of the cases.

Adolescent↗
PubMed1975

In vitro evaluation of cell-mediated immunity to Epstein-Barr herpesvirus by cell migration inhibition tests.

Migration of peripheral leukocytes in samples from sensitized [Epstein-Barr virus (EBV) antibody-positive] humans was greatly inhibited when challenged by antigen prepared from EBV-producing P3HR-1 cells but not by antigen prepared from EBV-nonproducing RAJI cells, EBV-negative human fibroblasts, or epithelial cells. Such inhibition was not observed when peripheral leuocytes from subjects or neonates not sensitized to EBV were challenged. Similar results were obtained in a two-stage test when the same leukocyte samples were challenged in vitro by antigen prepared from P3HR-1 cells and the cell-free supernatant was assayed for migration inhibition factor (MIF) in the guinea pig macrophage migration inhibition test; migration of guinea pig peritoneal exudate cells was greatly inhibited by the supernatant filtrates of leukocyte cultures only from subjects positive for EBV-antibody. Furthermore, this inhibitory effect was not observed if supernatant filtrates from leukocyte cultures challenged by antigens prepared from RAJI cells, fibroblasts, or epithelial cells were used. The EBV antigen transformed peripheral leukocytes and induced early antigen production in RAJI cells; however, a "killed" preparation (by UV irradiation) was sufficient for eliciting MIF production.

Antibodies, Viral↗