Sporadic cases of carriers of human T-lymphotropic virus type 1 in Southeast Asia.

Sera obtained from 3,472 persons in Malaysia, Thailand, Philippines and Indonesia were tested for the presence of antibody to adult T-cell leukemia-associated antigen by the gelatin particle agglutination test and indirect immunofluorescence. Among these, only two seropositives were identified. One was a 30-year-old male Malaysian of Indian origin.

Seroepidemiological survey on dengue and Japanese encephalitis virus infections in Asian monkeys.

To investigate the ecology of dengue and Japanese encephalitis (JE) viruses in the forest in Asia, a seroepidemiological survey was carried out on 358 Southeast Asian cynomolgus (Macaca iris), 33 Indian bonnet (Macaca radiata) and 37 Japanese (Macaca fuscata) monkey sera by a plaque reduction neutralization test. The results indicated that Southeast Asian monkeys were naturally infected with these viruses but the frequency of antibody to them varied considerably according to the geographical origin of the monkeys. The frequency of antibody to one or more types of dengue virus were 87.

Antigen-specific suppressor T lymphocytes in human lymphatic filariasis.

Immune responses to parasite antigens are much lower in patients with microfilaremia than in persons with other manifestations of brugian filariasis. To determine whether hyporeactivity is associated with changes in populations of lymphocytes that regulate immune responses, we quantitated helper and suppressor T cells in the blood of patients infected with Brugia malayi. Increased numbers of suppressor T cells were present in 15 of 17 patients with microfilaremia and in six of 11 patients with elephantiasis.

Effect of treatment with diethylcarbamazine on immune responses to filarial antigens in patients infected with Brugia malayi.

We studied the effect of treatment with diethylcarbamazine (DEC) on immune responses to parasite antigens in humans infected with Brugia malayi. In vitro lymphocyte proliferative responses to microfilarial antigens increased in patients who became amicrofilaremic after treatment with DEC. No changes in reactivity were observed in amicrofilaremic individuals who were given DEC or in a small number of patients who remained microfilaremic after treatment.