The first experimental immunization of humans against the AIDS retrovirus, HIV-1, was started in a series of HIV seronegative, healthy volunteers in November 1986. For the primary vaccination recombinant vaccinia virus (V25) expressing the complete gp160 env protein of the HTLV-IIIB strain of HIV-1 was introduced by scarification. This elicited a weak primary response which we subsequently attempted to enhance by additional immunizations (boosting), using four different immunization protocols. We report here that intravenous injection of paraformaldehyde-fixed autologous cells infected in vitro with V25 (individual D.Z.) gave the best results. This individual received second and third boosts of intramuscular gp160 derived from an HTLV-IIIB clone using the hybrid vaccinia virus/bacteriophage T7 expression system. An anamnestic humoral and cellular immune reaction was achieved for over one year after the original vaccination, with high levels of antibodies to the viral envelope, and neutralizing antibodies against divergent HIV-1 strains such as HTLV-IIIB and HTLV-IIIRF (also called HTLV-III HAT) after the first boost. In addition, group-specific cell-mediated immunity and cell-mediated cytotoxicity against infected T4 cells were obtained after the primary vaccine and enhanced by the boosts. Finally, skin tests showed both immediate and delayed hypersensitivity to gp160 in vivo. Although this protocol is not practical for a large scale vaccine trial, our results show for the first time that an immune state against HIV can be obtained in man.

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IgG, IgM, and IgE antibodies against the filaria Loa loa were measured in umbilical cord blood and in blood from young Gabonese children by an ELISA technique using a homologous metabolic antigen. For children in eight consecutive age groups and adults the percentage of the population positive for each of the antibody classes was determined. The number of children with maternal IgG decreased until one year of age when new synthesis began to become apparent. 1gM antibodies were detected only after six months, probably indicating an early infancy as opposed to a fetal infection. The percentage of individuals positive for IgM or IgEE reached a peak between two and three years old, followed by a slight decline. Over half of the individuals over one year of age had IgM antibody against L. loa, indicating long-term synthesis of this class of immunoglobulin in many people. In the first two years of life, IgE antibodies were usually accompanied by L. loa-specific IgM. This specific IgE did not appear to trigger the synthesis of nonspecific IgE. By the age of two, 95°-(, of the population had some antibodies against L. loa and by five the percentage of individuals positive for each antibody class had reached adult levels.Infestation with the filaria Loa loa is very common in certain parts of equatorial Africa and is highly endemic in Gabon (2,3,7,8). The diagnosis of Loa loa infec tionby microscopic identification of microfilariae in the blood does not reveal all infections, particularly in children where microfilariae are rarely seen (2).The development of an ELISA method for the determination of L. loa-specific antibodies that do not appear to cross-react with Dipetalonema perstans (4) has per mittedus to titrate not only IgG and IgM, but also IgE. This latter class of im munoglobulinis important in immediate hypersensitivity and in host-parasite interactions (6), but because of its low concentration in the blood, it is difficult to measure.In addition, total IgE has been measured as, according to Ishizaka et al (5), specific IgE synthesis primes the production of nonspecific IgE.In this investigation, we have studied the immunological status of Gabonese children in regard to L. loa in order to identify the age at which antibodies are first observed and the age at which the percentage of individuals positive for each class of immunoglobulin is the same as in adults. 787

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We evaluated the use of voluntary blood donor recruitment in Kinshasa, Zaire, as a means of reducing transmission of HIV-1 and other infectious agents by blood transfusion. Between January 1, 1989, and April 7, 1989, 2,237 blood donors were enrolled in the study at the transfusion centre of the Mama Yemo Hospital. Each donor was tested for antibodies to HIV-1 confirmed by IFA and Western blot, Treponema pallidum, antibodies to hepatitis B virus (HBV) core antigen and screened for the presence of the HBV surface antigen. Test results were related to the data of the blood donors: age, sex, haematocrit, voluntary blood donor, family member donor, paid donor. The serological results of all donors for Anti-HIV-1, Anti-HBc, HBsAg and TPHA were 4.8%, 70.9%, 13.1% and 13.3% respectively. Lower seroprevalence rates were found among voluntary blood donors. However, only TPHA seroprevalence was significantly lower in voluntary blood donors (8.4%, 23/275) compared with paid donors (15.2%, 87/571) (p<0.01). A greater proportion of voluntary donors provides a store of blood which allows more extensive screening of blood for HIV-1 and other infectious diseases. Voluntary blood donor recruitment is critical for the provision of safe blood supplies in Kinshasa.