Efficacy trial of a parenteral gonococcal pilus vaccine in men

Efficacy trial of a parenteral gonococcal pilus vaccine in men J o h n W . B o s l e g o * , E d m u n d C. T r a m o n t *~, R a y m o n d C. C h u n g * , D a n i e l G . M c C h e s n e y * , J e n n i e C i a k * , J e r a l d C. S a d o f f * , M y r o n V. P i z i a k * , J o e l D. B r o w n * , C h a r l e s C. B r i n t o n , Jr +, S a r a h W. W o o d + a n d J a m e s R. B r y a n *

A randomized, placebo-controlled, double-blind e[li'cacT trial q/'a pur(lied gonococcal pilus vaccine composed o f a single pilus type was tested in 3123 men and 127 women volunteers. Either 100 #g o f vaccine or a placebo was given intradermal O' on day 1 and day 14. Each group was evenly matched with respect to age, sex, prior history o f a sexually transmitted disease, sexual exposure during the study and attrition from the study. None q/" the women volunteers acquired gonorrhoea during the trial. In the male volunteers, 108 vaccine and 102 placebo recipients acquired gonorrhoea 15 days or later after the initial immunization. Vaccines developed a sustained E L I S A antibody response to homologous and heterologous pili, but the latter titres were approximateO, 40% as high as the homologous pilus antibody rises. There were, however, no increases in inhibition q / attachment antibody (lEA) titres'. Local antibodies (semen) against homologous and heterologous strains were also elicited (ELISA). The vaccine was sq/e and did not alter the clinical e.vpression o[" disease. This gonococcal pilus vaccine composed of a single pilus type ./ailed to protect men against gonococcal urethritis. Keywords: Neisseria #onorrhoeae; Neisseria gonorrhoeae pili; inhibition of attachment; local antibodies

INTRODUCTION Gonococcal infections continue to be a major health problem despite effective antibiotic therapy I 3. An effective vaccine would significantly reduce the morbidity and cost associated with gonorrhoea and since man is the only natural host, it might also lead to global eradication. Of all the cell surface structures of Neisseria gonorrhoeae, pili have been best correlated with virulence