EMERGENCE OF ANTIBODY TO CAPSULAR POLYSACCHARIDES OF STREPTOCOCCUS-PNEUMONIAE DURING OUTBREAKS OF PNEUMONIA - ASSOCIATION WITH NASOPHARYNGEAL COLONIZATION

Antibody to pneumococcal capsular polysaccharides (PPS) of Streptococc us pneumoniae plays a major role in protecting the host against pneumo coccal infection. ii variable proportion of healthy adults have antibo dy to PPS, often in the absence of recognized pneumococcal infection. To determine whether exposure to pneumococci or colonization by pneumo cocci, or both, stimulates the emergence of antibody to PPS, we studie d outbreaks of pneumonia at two military camps, Of the men who were pr esent at a military training camp during an outbreak of pneumonia due to S. pneumoniae serotype 1 but who did not develop pneumonia, 27.8% h ad IgG antibody to PPS 1, whereas only 3.6% of controls had this antib ody. In another outbreak caused by S. pneumoniae serotypes 7F and 8, 3 5.9% of asymptomatic soldiers who had nasopharyngeal colonization by o ne of these strains had antibody to the relevant PPS, and another 30.8 % who originally did not have antibody developed it within 30 days; th us, 66.7% of these soldiers had antibody to the relevant PPS, These da ta show that serotype-specific antibody promptly appears following exp osure to an outbreak of pneumococcal pneumonia and is probably mediate d through acquisition of nasopharyngeal pneumococcal carriage.