Epidemiological study of Taenia solium infections in a rural village in Honduras.

An epidemiological study was conducted in a Honduran rural community in 1991, to determine the local prevalence and associated risk factors of Taenia infection. The seroprevalence of anti-cysticercus antibodies, investigated by ELISA (N = 526), was found to be 30%. The prevalence of intestinal infections with Taenia and other parasites was investigated, by formol-ether concentration of three stool samples from each subject (N = 536). Almost all (96%) of the subjects carried at least one of the 17 species of intestinal parasite identified, 11 (2%) of them (nine of them female) being found to be infected with Taenia spp. When nine of these 11 were given niclosamide, four expelled Taenia segments, all of which were identified as T. solium after carmine staining. Risk factors associated with seropositivity were earthen floor, overcrowding, previous taeniasis and living in the same household as a person reporting previous taeniasis. Four years later (1995), a follow-up study in a sub-sample of the previously studied population revealed that 34% of the subjects were seropositive for anti-Taenia solium antibodies (as determined by a cysticercosis-specific, enzyme-linked, immunoelectrotransfer, blot assay) and that 1.5% had taeniasis. Taeniasis and cysticercosis therefore appear to be important public-health problems in rural areas of Honduras, as they are in other countries of Latin America. Large-scale studies need to be conducted to facilitate the design of programmes to control these diseases.

Epstein-Barr virus and childhood Hodgkin's disease in Honduras and the United States.

In industrialized populations, Hodgkin's disease (HD) has an initial peak in young adulthood, whereas in economically developing populations the initial peak occurs in childhood. This pattern resembles that of infection with poliovirus and suggests an infectious cofactor in the etiology. Serologic studies have linked Epstein-Barr virus (EBV) to young adult and adult HD, and viral nucleic acids and antigens have been detected in a subset of Hodgkin's tumor specimens. To investigate the association of childhood HD with EBV we studied tumor specimens from 11 children treated in Honduras and 25 children treated in the United States using in situ hybridization and antigen detection techniques. Among the patients from Honduras, tumor specimens from all cases were EBV positive. Among the patients from the United States, tumor specimens from six of seven patients with mixed cellularity histology, 2 of 15 with nodular sclerosis histology, and neither of two patients with lymphocyte-predominant histologies were EBV positive. These findings support the hypothesis that EBV contributes to the pathogenesis of HD in children, particularly in mixed cellularity HD, and raises the possibility that there are important geographic, racial, or ethnic factors in the EBV association with HD.

Trypanosomatid isolates from Honduras: differentiation between Trypanosoma cruzi and Trypanosoma rangeli.

With the aim of identifying and differentiating Trypanosoma cruzi from Trypanosoma rangeli, culture epimastigotes from 30 Honduran trypanosomatid isolates were analyzed by susceptibility to complement lysis, reactivity to lectins, reactivity to monoclonal antibodies specific for T. cruzi, and isoenzymatic electrophoretic patterns. Using these four methodologies, 27 of the 30 trypanosomatid isolates, as well as 5 clones, were identified as T. cruzi, whereas the remaining three isolates were classified as T. rangeli. None of the isolates presented mixed trypanosome species. Results indicate that both trypanosomatid species circulate in Honduras and that any of the four methods employed may be used to reliably differentiate T. cruzi from T. rangeli.

Gonorrhoea and urogenital chlamydial infection in female prostitutes in Tegucigalpa, Honduras.

The prevalence of gonorrhoea and urogenital chlamydial infection was investigated in female prostitutes in Tegucigalpa, Honduras. Epidemiological data were recorded according to a standardized questionnaire. The median age of the prostitutes was 27 years and the median period of prostitution was 2-4 years. Most of the women (91%) had no occupation other than prostitution and 57% of them had not even completed primary school. In 233 cases when both gonococcal culture and chlamydial antigen detection with a commercial EIA kit were performed the prevalence of gonorrhoea was 25% (59) and that of chlamydial infection 31% (72). Both diseases were recorded in 9%. The women who had been prostitutes for 2 years or longer had gonorrhoea (P less than 0.01) or chlamydial infection (P less than 0.05) less frequently than those who had practised prostitution for a shorter time period. Among 70 different gonococcal isolates from 241 prostitutes, 40 (57%) belonged to serogroup W II/III. Most (83%) of the 30 W I isolates were beta-lactamase producing (PPNG) like 42% of the W II/III isolates. All non-PPNG isolates, except one had decreased susceptibility to benzylpenicillin (MIC greater than or equal to 0.125 mg/l) and all isolates were susceptible to spectinomycin. Four out of five isolates from the throat were PPNG and the fifth had a benzylpenicillin MIC of 0.5-2.0 mg/l.

PIP: The prevalence of gonorrhea and urogenital chlamydia infection was investigated among female prostitutes in Tegucigalpa, Honduras. Epidemiological data were recorded according to a standardized questionnaire. The median age of the prostitutes was 27 years old and median period of prostitution was 2-4 years. Most of the women (91%) has no other occupation besides prostitution and 57% of them had not even completed primary school. Among 233 cases when both gonococcal culture and chlamydial antigen detection with a commercial EIA kit were performed, the prevalence of gonorrhea was 25% (59) and that of chlamydial infection 31% (72). Both diseases were recorded in 9%. The women who had been prostitutes for 2 or more years had gonorrhea (p0.01) or chlamydial infection (p0.05) less frequently than those who had practiced prostitution for a shorter time period. Among 70 different gonococcal isolates from 241 prostitutes, 40 (57%) belonged to serogroup W II/III. Most (83%) of the W I isolates were beta-lactamase producing (PPNG) as were 42% of the W II/III isolates. All non-PPNG isolates except 1 had decreased susceptibility to benzylpenicillin (MIC or= o.125 mg/1) and all isolates were susceptible to spectinomycin. 4 of 5 isolates from the throat were PPNG and the 5th had a benzylpenicillin MIC of 0.5-2.0 mg/l.

Human immunodeficiency virus infection and syphilis in Hondurian female prostitutes.

The seroprevalence of human immunodeficiency virus (HIV) infection and syphilis was investigated in 181 female prostitutes in Tegucigalpa, Honduras. One particle agglutination test and two enzyme immunoassays, as well as one immunofluorescence test were used for the screening of HIV antibodies. Confirmation of positive results by the screening tests was carried out by Western blot. The prevalence of HIV seropositivity was 4% (8 women). Specific treponemal antibodies were found in 50% (90/181) of the prostitutes as judged by Treponema pallidum haemagglutination assay (TPHA) and/or fluorescent treponemal antibody-absorption (FTA-ABSIgG) test. As estimated by the positivity of any or both non-treponemal tests (VDRL and RPR), a total of 31 (17%) out of the 181 women had active syphilis. A good correlation was found between the results obtained by TPHA and FTA-ABSIgG. IgM antibodies were found in 72% of sera positive by TPHA and/or FTA-ABSIgG. Four out of the 181 women were found to have antibodies to both HIV and Treponema pallidum.

PIP: The seroprevalence of human immunodeficiency virus (HIV) infection and syphilis was investigated among 181 female prostitutes in Tegucigalpa, Honduras. 1 particle agglutination test and 2 enzyme immunoassays, as well as 1 immunofluorescence test, were used for the screening of HIV antibodies. Confirmation of positive results by the screening tests was carried out by western blot. The prevalence of HIV seropositivity was 4% (8 women). Specific treponemal antibodies were found in 50% (90/181) of the prostitutes as judged by Treponema pallidum hemagglutination assay (TPHA) and/or fluorescent treponemal antibody-absorption (FTA-ABSIgG) test. As estimated by the positivity of any or both nontreponemal tests (VDRL and RPR), a total of 31 (17%) of 181 women had active syphilis. A good correlation was found between the results obtained by TPHA and FTA-ABSIgG. IgM antibodies were found in 72% of sera positive by TPHA and/or FTA-ABSIgG. 4 of 181 women were found to have antibodies to both HIV and Treponema pallidum.

Idiotypic profile of the response to phosphorylcholine induced in the absence of the homologous antigen.

In the absence of the homologous antigen, an anti-phosphorylcholine (PC) plaque-forming cell (PFC) response has been induced in vitro which is restricted to the TEPC 15 idiotype (T15). Anti-T15 antibodies were used to focus either the keyhole limpet hemocyanin (KLH) or the fowl gamma-globulin (FGG) carrier molecules on the membrane of B cells carrying the T15 idiotype on their immunoglobulin receptors; thereafter, these cells were allowed to cooperate in vitro for 5 days with T cells primed to the appropriate carrier molecule. A response, virtually 100% T15+, could be induced both in normal BALB/c and in T15 neonatally suppressed mice which had lost the T15+ clonal dominance. The magnitude of this response is comparable to that obtained in the presence of the PC antigen. The role of the membrane-bound immunoglobulin receptor (sIg) in the expression of different anti-PC clones was also investigated. We have focused either the KLH or the FGG carrier molecules on the membrane of B cells via anti-H-2 antibodies and then cultured these cells for 5 days with the appropriate carrier-specific T cells. Under these conditions, B cells are activated in the absence of interaction at the sIg. The idiotypic profile of the anti-PC PFC obtained with the anti-H-2-mediated activation was then compared with the profile of the anti-PC response obtained in the presence of PC antigen. Since similar idiotypic profiles were obtained in both cases, it can be excluded that sIg plays a direct role in favoring the expression of T15+ over T15- anti-PC clones.

Enrichment of hapten-specific helper T cells using anti-immunoglobulin combining site antibodies.

Spleen T cells from phosphorylcholine (PC)-primed BALB/c mice were indirectly stained with affinity column-purified heterologous rabbit anti-TEPC 15 (T 15) antibodies. These antibodies were shown to be directed towards antigenic determinants in or near the combining site of T 15 in that their interaction with the myeloma protein was more than 95% inhibitable by PC. The stained cells were sorted into "bright" and "dull" fractions using a fluorescence-activated cell sorter. Sorted populations were then assessed for enrichment and depletion of PC-specific helper activity using an in vivo adoptive transfer assay. The results indicate that the staining procedure employed enabled the specific enrichment of PC helper T cells and therefore suggest that these T cells bear combining site structures similar to that of the myeloma protein T 15.

Evidence for the endogenous production of T cell receptors bearing idiotypic determinants.

Unprimed thymus-derived (T) cells from spleens of either conventional TEPC 15+ (T15+) BALB/c mice or neonatally suppressed T15- BALB/c mice were used to reconstitute neonatally suppressed T15- BALB/c nude mice and conventional T15+ BALB/c nude mice, respectively. In so doing, the idiotypes produced by phosphorycholine (PC)-specific bone marrow-derived (B) cells were dissociated from idiotypes putatively produced by PC-specific T cells. Subsequent to priming of the reconstituted BALB/c nude mice with either anti-T15 antisera or PC-MOPC 315, their splenic T cells were assessed for PC-specific helper activity and expression of the T15 idiotype. Our results indicate that expression of the T15 idiotype by T cells as determined by (a) the ability to prime PC-specific helper cells with anti-T15 antibodies, and (b) the ability to inhibit PC-specific helper function with anti-T15 antibodies, depended on the idiotype of the unprimed donor T cell source and not that of the B cells in the reconstituted recipients. We conclude that the idiotype-bearing T cell receptor specific for PC is not a passively adsorbed B cell product.

Idiotype suppression by maternal influence.

In BALB/c mice, antibodies to the alpha-(1-3) glucosidic linkage of some dextrans (Dex) carry the idiotype of the BALB/c myeloma protein J558. Both specific antibody and idiotype are inherited in a dominant fashion, linked to the immunoglobulin (Ig) (heavy chain) allotype Igla of BALB/c mice (Eur. J. Immunol. 1975. 5: 775). In F1 hybrid mice from the parent strains SJL and BALB/c, we were able to suppress the expression of anti-Dex antibodies by immunizing prospective SJL mothers to the J558 idiotype. The state of suppression in the progeny was ascertained by immunization with Dex, and tests for the following were carried out: (a) antibodies specific for Dex; (b) inhibition of such antibodies (if present) by antiidiotypic serum to protein J558; (c) presence of the J558 idiotype; and (d) concentration of lambda1 chains (which are associated with the 558 idiotype) in the serum. SJL mothers, once immunized, conferred suppression upon several successive litters, spanning a period of 4-5 months. Suppression in F1 progeny animals lasted for 16 weeks or more. Spleen cells from suppressed F1 mice which had neither been treated with Dex nor with J558 protein, were able to confer suppression to further F1 newborn mice.

Induction and characterization of "autologous" anti-isiotypic antibodies.

Upon immunization with phosphorylcholine (PC), conventional BALB/c mice produce anti-PC antibodies bearing predominantly the idiotype characteristic of the BALB/c PC-binding myeloma protein TEPC 15 (T15). To investigate whether BALB/c mice are able to produce antibodies to the autologous T15 idiotype, conventional (T15-positive) and neonatally suppressed (T15-negative) BALB/c mice were immunized with purcific for the T15 idiotype. However, anti-T15 antibodies were more readily induced in neonatally suppressed mice which in turn produced higher anti-T15 titers than conventional mice. Such "autologous" anti-T15 antibodies are able to (a) change the idiotypic pattern of the anti-PC response of conventional BALB/c mice in situ and, (b) inhibit the induction of an anti-PC response in vitro by spleen cells from T15-positive but not T15-negative BALB/mice. Thus, BALB/c mice are capable of producing anti-T15 antibodies upon immunization with an isologous myeloma protein which bears the autologous T15 isiotype. We suggest that isiotypes should not be strictly considered as "self-antigens" since the dramatic increase in their concentration, subsequent to antigen stimulation, might confer upon them immunogenic properties not shared by self-antigens.

Expression of new idiotypes following neonatal idiotypic suppression of a dominant clone.

The anti-PC antibodies of BALB/c origin bear predominantly the idiotype characteristic of the phosphorylcholine (PC)-binding T15 idiotype than sera from adult mice, and, unlike the latter, they also contain detectable amounts of anti-T15 antibodies. By 2 weeks of age the anti-T15 antibodies are no longer detectable while the T15 idiotype has reached adult levels. Injection of neonatal mice with anti-idiotypic antibodies renders them unresponsive to PC until the 15th week of life. Furthermore, this treatment induces a chronic suppression of the T15 idiotype, since on recovery from unresponsiveness, the neonatally suppressed mice produce anti-PC antibodies which are predominantly T15-negative. In contrast, treatment of adult mice with anti-idiotypic antibodies induces only a transient state of unresponsiveness to PC, and the antibodies produced upon recovery bear the T15 idiotype. These findings are discussed in the context of idiotype anti-idiotype interactions and their possible role in immuno-regulation.

Antibody response to phosphorylcholine in vitro. II. Analysis of T-dependent and T-independent responses.

Spleen cells from BALB/c mice primed with keyhole limpet hemocyanin (KLH), were stimulated with heat-killed vaccine of rough Pneumococcus pneumoniae R36A (Pn) and/or phosphorylcholine (PC)-coupled KLH to induce an anti-PC response in vitro. The response to PC-KLH was found to be T-dependent while it is T-independent to Pn. The antibodies induced with either antigen had similar avidity and expressed the TEPC 15 idiotype exclusively; thus T cell involvement in the response to PC-KLH failed to alter these parameters of the anti-PC response. At the precursor cell level, Pn induced small clones with an average size of 10 plaque-forming cells (PFC), whereas PC-KLH gave rise to larger clones of 40-50 PFC. This difference in the proliferative potential of PC precursor B cells hinted at the possibility that Pn and PC-KLH were stimulating different precursors. This was corroborated by the observation that a) when Pn and PC-KLH were added to the same cultures a synergistic effect was seen, i.e. the number of plaques was greater than the sum of the responses induced by each antigen, and b) in microcultures, under conditions limiting B cells only, Pn plus PC-KLH induced a higher fraction of responding wells than either antigen on its own. We postulate that Pn and PC-KLH stimulate subpopulations of PC precursor cells which are T-independent and T-dependent, respectively.