Cytotoxic T lymphocyte responses to vaccinia virus antigens but not HIV-1 subtype E envelope protein seen in HIV-1 seronegative Thais.

The HIV-1 prime boost phase I/II vaccine trial using a recombinant canarypox vector, vCP1521, containing subtype E env (gp120), and subtype B env (gp41), gag and protease has started in Thailand. We have demonstrated that although 4 from 15 human immunodeficiency virus type 1 (HIV-1) seronegative Individuals showed cytotoxic T lymphocyte (CTL) responses to vaccinia virus antigens, none of them showed specific CTL responses to subtype E Env after in vitro stimulation. This preliminary study suggests that specific CTL responses to subtype E envelope detected in HIV-1 seronegative Individuals after vaccination should be considered as specific responses to the immunization.

Specific IgA antibody to Epstein-Barr viral capsid antigen: a better marker for screening nasopharyngeal carcinoma than EBV-DNA detection by polymerase chain reaction.

Nasopharyngeal carcinoma (NPC) is strongly associated with Epstein-Barr virus (EBV) infection. To assess whether EBV DNA detection by polymerase chain reaction (PCR) or presence of specific serum antibody to viral capsid antigen (VCA) was a better marker for screening NPC, nasopharyngeal tissues and blood samples from 58 NPC patients and 24 non-NPC patients (23 with laryngotracheal stenosis and 1 with chronic tonsillitis) were tested for the presence of EBV DNA and serum specific VCA antibodies, respectively. EBV DNA was detected in 56 (96.5%) of NPC patients and 15 (62.5%) of non-NPC controls, with predominantly EBV type A in both groups. On the other hand, specific VCA IgA antibody was detected in the majority of NPC patients: 52 (89.7%) while only 4 (16.7%) were detected in non-NPC controls. Therefore, specific VCA IgA antibody may serve as a better marker for screening NPC than EBV DNA detected by PCR.

Prevalence of type specific Epstein-Barr virus in the genital tract of genital herpes suspected patients.

A total of 62 clinical specimens from the genital tract of patients who were suspected of contracting genital herpes were investigated for HSV infection by the virus isolation method, and also investigated for the co-infection with EBV infection by detecting EBV DNA using nested PCR. HSV infection was diagnosed in 30 (48.4%) of the study cases, and so was EBV. EBV DNA was present in 17 (56.7%) of the 30 HSV positive samples. No correlation was found between the co-existence of these two viruses together. EBV DNA was detected in genital specimens of cervical, vaginal, urethral, and anal swabs. Ninety per cent of EBV belonged to type 1, and the remainder belonged to type 2 and mixed types. The role of EBV in genital tract infection needs to be further investigated.

Regulation of IFN consensus sequence binding protein expression in murine macrophages.

Recent work has demonstrated that the transcription factor, IFN consensus sequence binding protein (ICSBP), plays a critical role in the capacity of mice to control infection with Toxoplasma gondii and Leishmania major, agents that require highly activated macrophages for their elimination. In this report the regulation of ICSBP mRNA and protein were analyzed in murine macrophages stimulated with LPS and/or IFN-gamma. Like induction of leishmaniacidal activity, LPS and IFN-gamma synergize to induce ICSBP mRNA and protein. Deletion analysis of the ICSBP promoter identified regions that were IFN-gamma responsive, regions that mediate the ability of LPS and IFN-gamma to activate this promoter synergistically, as well as regions that normally repress ICSBP transcription. Finally, exogenous expression of ICSBP, found in previous studies to down-regulate MHC I gene expression, failed to repress basal or IFN-gamma-induced ICSBP transcription. This demonstrates that ICSBP can selectively suppress the expression of IFN-responsive genes. These findings extend in a significant way our understanding of the regulation of ICSBP by LPS and IFN-gamma and provide important clues as to its role in macrophage activation.

A hospital-based study of acute viral infections of the respiratory tract in Thai children, with emphasis on laboratory diagnosis.

The hospital-based study described here examined the viruses found in 738 children less than 5 years old who presented at Ramathibodi Hospital, Bangkok, Thailand, from January 1986 to December 1987 with acute respiratory tract infections. Three methods for detection of viral infection are compared: direct examination of epithelial cells of the respiratory tract with the use of fluorescent antibody staining, isolation of virus, and measurement of antibody in acute- and convalescent-phase sera. Viral infections were found in 44.7% of the study population. Diagnosis by the examination of epithelial cells with the fluorescent antibody staining procedure was found to have several deficiencies; however, this technique was the most sensitive for diagnosis of infection due to respiratory syncytial virus. Isolation of virus was the best method for identification of adenoviruses, parainfluenza 1 and 3 viruses, and influenza B virus. Problems associated with serodiagnosis included failure to obtain specimens of convalescent-phase blood in 24.5% of cases and insensitivity of serodiagnosis for young children except for the identification of antibody to influenza A virus. The combination of all three tests yielded the best rate of detection of virus.