ACUTE RESPIRATORY DISEASE IN NORMAL VOLUNTEERS ASSOCIATED WITH COXSACKIE A-21 VIRAL INFECTION. III. RESPONSE TO NASOPHARYNGEAL AND ENTERIC INOCULATION

Abstract

Studies were made in normal volunteers in which an enterovirus, Coxsackie A-21, was administered by coarse spray and pipette into the nasopharynx or by enteric-coated capsule and Rehfuss tube into the intestinal tract. Subjects with no, intermediate, and high titers of homologous antibody were used. The study revealed that nasopharyngeal inoculation of the no antibody group with 3000 mean tissue culture infective dose (TCID50) of virus was followed by a systemic illness with fever and myalgia. Illness was more severe when the inoculum was 320,000 TCID50. The presence of intermediate amounts of antibody (14 to 1:128 neutralizing, 1:10 to 1:40 hemagglutina-tion-inhibiting) before inoculation was associated with a syndrome of common cold, whereas men with high titers (> 1:28 neutralizing, [greater than or equl:40 hemagglutination-inhibiting) exhibited no illness. The agent, although designated an enterovirus, was isolated most frequently from throat swabs. This finding was confirmed when it was found that direct intestinal inoculation with 320,000 TCID50 of virus produced only transient infection and no illness or antibody response.