A population from the Wuchereria bancrofti-endemic island of Mauke was reevaluated retrospectively by use of the Og4C3 circulating antigen (CAg) enzyme-linked immunosorbent assay to assess active infection in relation to host responses by age and gender. Use of microfilaremia (Mf) alone misclassified 50% of infected people, although CAg and Mf levels were positively correlated. Levels of CAg peaked between those aged 31-60 years; men aged 60 years had a significantly higher CAg prevalence (90%) than women. Filaria-specific im-munoglobulin (Ig) G4 reached maximum levels in both genders at age 51-60 years. By analysis of variance, both age and gender significantly influenced CAg and IgG4, with men having higher levels of both in the total population. Individuals positive for CAg had significantly lower lymphocyte proliferation responses to parasite antigen than did CAg-negative people, regardless of clinical status. This study reemphasizes the importance of CAg measurements for accurately assessing filarial prevalence and clinical status and demonstrates the relationship between active infection and immune responsiveness.

Lymphoproliferation and gamma interferon (IFN-y) secretion in response to 28 overlapping 20-mer synthetic peptides covering the complete sequence of the mature (295-amino-acid) 85A component of the major secreted, fibronectin-binding antigen 85 complex from Mycobacterium tuberculosis and Mycobacterium bovis BCG (MTAg85A) was examined by using peripheral blood mononuclear cell (PBMC) cultures from healthy tuberculinand lepromin-positive volunteers and from patients with tuberculosis and leprosy. Peptide recognition was largely promiscuous, with a variety of human leukocyte antigen haplotypes reacting to the same peptides. PBMC from all tuberculin-positive subjects reacted to Ag85, and the majority proliferated in response to peptide 6 (amino acids 51 to 70), peptides 13, 14, and 15 (amino acids 121 to 160), or peptides 20 and 21 (amino acids 191 to 220). PBMC from tuberculosis patients demonstrated a variable reactivity to Ag85 and its peptides, and the strongest proliferation was observed against peptide 7 (amino acids 61 to 80). MTAg85A peptides were also recognized by PBMC from healthy lepromin-positive volunteers and paucibacillary leprosy patients (again in a promiscuous manner), but despite a 90%o homology between the 85A proteins ofM. leprae and M. tuberculosis, the peptides recognized were different. PBMC from lepromin-positive healthy contacts reacted against peptide 2 (amino acids 11 to 30), peptide 5 (amino acids 41 to 60), and peptides 25 and 26 (amino acids 241 to 270). PBMC from paucibacillary patients reacted preferentially against peptide 1 (amino acids 1 to 20) and peptide 5. Multibacillary patients were not reactive to Ag85 or the MT85A peptides. IFN-y production was generally detected simultaneously with positive lymphoproliferative responses, although peptide 1 mostly stimulated proliferation and peptides 27 and 28 mostly elicited an IFN-y response. In conclusion, regions 41 to 80 and 241 to 295 demonstrated powerful and promiscuous T-cell-stimulatory properties, resulting in proliferative responses and IFN-y secretion, respectively, in the majority of reactive

No abstract

An international multicenter study of ready-to-eat foods, sandwiches, and ice creams or sorbets sold in the streets and their vendors was carried out to assess the microbiological quality of these foods and to identify characteristics of the vendors possibly associated with pathogens. Thirteen towns in Africa, America, Asia, and Oceania were involved in the study. A single protocol was used in all 13 centers: representative sampling was by random selection of vendors and a sample of foods bought from each of these vendors at a time and date selected at random. Microbiological analyses were carried out using standardized Association Française de Normalisation methods, and the use of a standardized questionnaire to collect data concerning the characteristics of the vendors. Fifteen surveys were carried out, with 3,003 food samples from 1,268 vendors. The proportion of unsatisfactory food samples was between 12.7 and 82.9% for ice creams and sorbets and between 11.3 and 92% for sandwiches. For ice creams and sorbets, the sale of a large number of units (>80 per day) increased the risk of unsatisfactory food by a factor of 2.8 (95% confidence interval [CI]: 1.5 to 5.1), lack of training in food hygiene by 6.6 (95% CI: 1.1 to 50). and by a factor of 2.8 (95% CI: 1.4 to 5.4) for mobile vendors. These risk factors were not identified for sandwiches, this difference may be due to the presence of a cooking step in their preparation. These results show that the poor microbiological quality of these street foods constitutes a potential hazard to public health, that the extent of this hazard varies between the cities studied, and that vendors' health education in food safety is a crucial factor in the prevention of foodborne infections.

Three synthetic antigens related to the natural antigen phenolic glycolipid I (PGL-I) were compared for their efficacy in detecting leprosy when used as antigens in an enzyme-linked immunosorbent assay (ELISA) for IgM antibody to PGL-I. Absorbance values for ELISAs using the three antigens correlated well (.79 less than r less than .99) and had a high rate of agreement (89.5% less than a less than 98.4%). Of three subjects (household contacts of patients with leprosy) who later developed the disease, one with lepromatous and one with indeterminate leprosy were seropositive by ELISAs using the three antigens before the clinical onset of disease; one who developed borderline tuberculoid leprosy was seronegative. The predictive value of a positive result for the test was very low (less than 2.4%) and the predictive value for a negative result was high (greater than 99.9%) because of the low prevalence of leprosy in French Polynesia (1.78 per 1000). The high sensitivity, specificity, and efficiency of the tests using the three antigens confirmed their great value for serodiagnosis of leprosy, especially the multibacillary form; the ELISA using NTP seems to be more specific and sensitive for detecting the paucibacillary form.