Mycobacterium bovis (BCG) infection of the lymph nodes of normal, immune, and cortisone-treated guinea pigs.

Abstract

Strain-2 inbred guinea pigs were infected intradermally with 10(5)-10(7) viable BCG (Pasteur) organisms by means of multiple scarifications of shaven midflank skin. The spread of the BCG to the draining lymph nodes and on to the spleen was followed quantitatively for 28 days. The population of bacilli at the inoculation site increased as much as tenfold the first 14 days. The number of viable BCG organisms recovered from the primary draining superficial dorsal axillary and inguinal lymph nodes varied from 0.1 to 1.0% of the inoculum, with a further tenfold to 100-fold drop in counts for the secondary subclavian and lumbar lymph nodes. The bacterial counts for the various nodes increased substantially the first 14 days. By 28 days, as many as 1,000 viable bacilli were recovered from the spleen. Increasing the inoculum size or the number of inoculation sites increased the primary node counts and promoted a more extensive and rapid spread by the BCG population to the secondary lymph nodes and spleen. Prior vaccination of the host with living BCG decreased the spread of the BCG inoculum from the scarification site to the various draining lymph nodes. Multiple injections of cortisone tended to reverse this effect.