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Activation of the innate immune system by different homotopes may direct the subsequent specific immune response, and as a consequence may have significant implications on vaccination. In this study, effects of i.v. administered lipopolysaccharide (LPS), and lipoteichoic acid (LTA), respectively, and s.c. administered Keyhole Limpet Hemocyanin (KLH) on total and isotype-specific (IgM and IgG) primary and secondary antibody responses of chickens to human serum albumin (HuSA) were determined. Similarly, effects of pre-treatment of the birds with the homotopes on primary antibody responses to rabbit gamma globulin (RGG) were measured. In addition, antigen-specific (HuSA and RGG) and mitogenic (concanavalin A, Con A) responses of peripheral blood leucocytes in vitro were also measured. Our findings confirm earlier observations that both LTA as well as LPS have immunomodulatory features in chickens, albeit in an opposite direction. LTA enhanced primary and to a minor degree secondary antigen-specific antibody titers, but LPS was found to suppress these responses. In RGG-primed birds, LPS enhanced a non-antigen-specific recall response to HuSA. In addition, KLH acted in an immunomodulatory role too, enhancing primary and secondary antibody responses, but suppressing non-specific cellular immunity in a non-antigen-specific fashion. Possible mechanisms underlying our observations, and the role of LTA, LPS, and KLH in polarization of the specific antibody response in chickens are discussed.

Objective: A greater understanding of minority adolescents' involvement in sex and violence is an essential precursor to the development of effective prevention programs targeted at inner-city youths., Method: To estimate the prevalence of involvement in sexual, assaultive, and suicidal behaviors and to quantify the relative importance of demographic, psychosocial, and behavioral risk factors for those behaviors, a survey was administered in the spring of 1992 to a sample of 3,738 predominantly Hispanic and African-American students attending four junior high schools in an economically disadvantaged, medically underserved New York City school district. The mean age of participants was 13.5 years; 73.7% were Dominican, 6.9% were other Hispanic, and 10.4% were black., Results: Thirty-one percent of males and 7% of females reported involvement in sexual intercourse, 27% of males and 8% of females reported involvement in assaultive behavior and 10% of males and 19% of females reported suicide intentions/attempts. The primary risk factor for sexual intercourse was a belief that involvement in intercourse was common and acceptable among peers. The primary risk factor for assaultive behavior was adverse social circumstances. The primary risk factor for suicide intentions/attempts was symptoms of depression. The risk for involvement in each of the three investigated risk behaviors was substantially increased by involvement in the other two behaviors., Conclusions: These findings underscore the urgent need for comprehensive sex and violence prevention programs targeted at urban minority junior high school students and suggest factors that may identify students at highest risk.