Cytokine production in NK and NKT cells from Mycobacterium tuberculosis infected patients.

Tuberculosis, a major health problem in developing countries, has re-emerged in recent years in many countries. While it is accepted that various lymphocyte subsets are important responses to mycobacterial infection, the roles of NK and NKT cells in producing cytokines are still unclear. Thus we have evaluated, in Mycobacterium tuberculosis infection, the frequency of cytokine producing cells by flow cytometry. Of 30 individuals examined, 17 had clinical evidence of pulmonary tuberculosis while the rest showed no evidence of infection. Patients had a significantly higher number of IFN-gamma and IL-4-producing T cells compared to control subjects, but the ratio of IFN-gamma to IL-4-producing T cells was similar in both groups. There were no differences between cytokine profiles of NK cells in patients and control subjects. A significant increase in the number of NKT cells was observed in patients. A striking finding was the higher frequency of IL-4-producing NKT cells compared to IFN-gamma-producing cells. Moreover, individual NKT cell produced both IFN-gamma and IL-4. The preferential type of Thl or Th2 cells is due to mycobacterial strain, type of antigen presenting cells and stage of disease, all of which can lead to different patterns of cytokine production by variety of lymphocyte subsets.

Binding antibody to neutralizing epitope gp41 in HIV-1 subtype CRF 01_AE infection related to stage of disease.

The responsiveness of gp41 antibody against epitope ELDKWA in HIV-1 infected subjects is of importance in neutralizing viral infectivity and for being related to disease progression. In this study, antibody titers to this neutralizing epitope from HIV-1 infected subjects at asymptomatic and AIDS stages in Thailand were investigated by peptide ELISA. The results showed that the frequency of antibody production against this neutralizing epitope was low (15-35%). Moreover, antibody titers to this epitope in sera from AIDS patients were significantly lower than those in sera from asymptomatic subjects which were collected in the same year (p=0.001). Comparison between the past (1992-1994) and present (2002) sera from asymptomatic infected individuals revealed that the earlier panel contained lower antibody titers than the later panel did (p = 0.05). In addition, random sera for HIV-1 infected subjects who were infected by diverse genetic subtypes, (A through G) including CRF 01_AE, had low titers of antibody to this region as well. It is assumed that antibody production to this epitope is low and related to the stage of HIV-1 infection.