PRECHALLENGE ANTIBODIES - MODERATORS OF INFECTION-RATE, SIGNS, AND SYMPTOMS IN ADULTS EXPERIMENTALLY CHALLENGED WITH RHINOVIRUS TYPE-39

This study determined the influence of serum neutralizing antibody tit ers on infection rate, symptom manifestations, and provoked signs and pathophysiologies in adults experimentally exposed to rhinovirus type 39 (RV-39). Antibody status was determined for 151 healthy volunteers who were then cloistered in a hotel for 6 days. At the end of the firs t cloister day, the volunteers were challenged with RV-39 in a median tissue culture infective dose of 100. On each of the 6 days, a nasal e xamination was performed, symptoms were scored, and objective tests of nasal mucociliary function, nasal airway patency, secretion productio n, and middle ear pressures were completed. Both subjects and investig ators were blinded to the prechallenge serum homotypic antibody titers of the subjects. Four subjects presented with a wild virus and were e xcluded from the analysis. Of the 147 included subjects, prechallenge serum antibody titers to RV-39 were low (under 2) in 56 subjects, inte rmediate (2 to 8) in 51 subjects, and high (above 16) in 40 subjects, The high-titer group was significantly different from the low-titer gr oup with respect to viral shedding, symptom load, subjective extent of illness, and secretion production, as well as in the frequency of sub jects with abnormal nasal mucociliary clearance and posi tive middle e ar pressures. The study results document that for experimental RV-39 e xposure, high levels of homotypic serum neutralizing antibody titers a re associated with protection from infection and a lessened degree of disease expression, but not with a reduction of otologic complications .