CORRELATION BETWEEN VACUOLATING CYTOTOXIN PRODUCTION BY HELICOBACTER-PYLORI ISOLATES IN-VITRO AND IN-VIVO
INFECTION AND IMMUNITY
Authors: COVER, TL; CAO, P; LIND, CD; THAM, KT; BLASER, MJ
Abstract
Approximately 50 to 60% of Helicobacter pylori isolates produce a vacuolating cytotoxin in vitro. To assess cytotoxin production in vivo, we sought to determine whether infection with a Tox(+) H. pylori strain is associated with the presence of serum antitoxin antibodies. H. pylori isolates and serum samples were obtained from 30 patients, and serum samples were obtained from 20 uninfected patients as controls. Sera were tested by enzyme-linked immunosorbent assay for reactivity with the purified 87-kDa vacuolating cytotoxin, and the 30 H. pylori isolates were tested for vacuolating cytotoxin production. Supernatants from 14 (47%) of the 30 H. pylori isolates induced vacuolation of HeLa cells. Sera from the 30 H. pylori-infected patients reacted with the purified 87-kDa cytotoxin to a greater extent than sera from the uninfected controls for both immunoglobulin G (IgG) and IgA classes (P = 0.0004 and P < 0.0001, respectively). Serum IgG and IgA responses to the purified 87-kDa cytotoxin were higher among the 14 patients infected with Tox(+) strains than among the 16 patients infected with Tox(-) strains (mean optical densities + standard errors of the means of 0.603 +/- 0.11 versus 0.234 +/- 0.07 [P = 0.005] and 0.644 +/- 0.12 versus 0.341 + 0.08 [P = 0.04] for IgG and IgA, respectively). Infection with a Tox(+) strain compared with a Tox(-) strain was associated with increased antral polymorphonuclear leukocyte inflammation scores (P = 0.04). These data indicate that cytotoxin production by H. pylori isolates in vitro correlates with cytotoxin production in vivo and that infection with Tox(+) H. pylori isolates may be associated with increased antral mucosal polymorphonuclear leukocyte infiltration.
Influence of Toxoplasma gondii Infection on Male Fertility: A Pilot Study on Immunocompetent Human Volunteers
IRANIAN JOURNAL OF PARASITOLOGY
Authors: Colosi, Horatiu Alexandru; Jalali-Zadeh, Babak; Colosi, Ioana Alina; Simon, Laura Mihaela; Costache, Carmen Anca
Abstract
Background: This study was conducted to investigate the influence of Toxoplasma gondii infection on spermatic and hormonal parameters in a pilot sample of immunocompetent human male subjects. Methods: This cross sectional, observational pilot study on 60 immunocompetent human male subjects aged between 18 and 60 yr old was conducted between 2012-2013. Blind evaluation of serological markers of past T. gondii infection (TOX-IgG, TOX-IgM) was performed, along with individual spermiograms and determinations of follicle-stimulating hormone (FSH) and testosterone serum levels. Results: The overall prevalence of past T. gondii infection in the investigated immunocompetent male subjects was 25%. No statistically significant influence of T. gondii infection on sperm characteristics (ejaculate quantity, sperm count, motility, morphology) and serum levels of FSH or testosterone were found. Among possible predictors of a modified spermiogram studied by multiple logistic regression along with the T. gondii infection (age, smoking, alcohol consumption, fertility influencing malformations, infections, trauma or medication), only the presence of varicocele in the medical history of the studied subjects was found to significantly participate in the prediction of a modified spermiogram (P=0.0154). A necessary sample size of 994 subjects was computed in order to achieve a test power of 0.8 (80%) to discriminate an effect size of 8.89% estimated by our pilot study. Conclusions: Although our investigation did not demonstrate an influence of latent T. gondii infection on spermatic and hormonal parameters of immunocompetent male humans, the absence of such an influence cannot be affirmed, due to the limited sample size of our pilot study.