Specific Antibody Levels in the Intestinal Perfusates of <i>Heligosomoides polygyrus</i>-lnfected Mice

Radial immunodiffusion analysis was performed on intestinal perfusates from ICR/CD&lt;sub&gt;1&lt;/sub&gt; mice following oral infection and challenge with viable &lt;i&gt;Heligosomoides polygyrus &lt;/i&gt;larvae. Infection of these mice resulted in an alteration in the amount and class of immunoglobulins, as well as anti-parasitic antibody. Specific IgA peaked at 3 days post-infection and then showed a gradual decline until day 21. This rapid elevation in IgA levels was temporally associated with early events in the parasite life cycle, and the increase in IgA was significantly higher in mice infected twice with &lt;i&gt;H. polygyrus &lt;/i&gt;prior to challenge. Differences in both the concentrations and kinetics of specific IgA and IgG&lt;sub&gt;1&lt;/sub&gt; were also observed in the perfusates from these mice when compared to those noted for animals infected only once.</jats:p

Effect of Infection with &lt;i&gt;Trichinella spiralis&lt;/i&gt; and BCG on Thymic Histology

The histology of mouse thymic tissue was examined following infection with &lt;i&gt;Trichinella spiralis&lt;/i&gt; and/or BCG. 1CR/CD-1 mice were orally infected with 200 &lt;i&gt;T. spiralis&lt;/i&gt; 56 days preceding intravenous administration of 4 × 10&lt;sup&gt;6&lt;/sup&gt; viable BCG. Following assessment of delayed hypersensitive foot pad reactions to BCG, the mice were bled and sacrificed. The thymus was removed from each animal, fixed in 10% neutral buffered formalin, embedded in paraffin and cut in 4 &lt;i&gt;μ&lt;/i&gt;m sections. Examination of serial sections indicated that &lt;i&gt;T. spiralis&lt;/i&gt; and &lt;i&gt;T. spiralis&lt;/i&gt;-BCG infections induced distinct anatomical changes within the thymic cortex and medulla, which may be related to previously described functional alterations of the immune system.</jats:p

Effect of &lt;i&gt;Trichinella spirali&lt;/i&gt;&lt;i&gt;s&lt;/i&gt; Infection on the Cell-Mediated Immune Response to BCG

Mice infected with &lt;i&gt;Trichinella spiralis&lt;/i&gt; have shown resistance to both intravenous and intraperitoneal infection with &lt;i&gt;Listeria monocytogenes&lt;/i&gt;. Since protection against &lt;i&gt;L. monocytogenes&lt;/i&gt; is mediated by cellular immunity, the effect of infection with &lt;i&gt;T. spiralis&lt;/i&gt; on the immune response to BCG was investigated. ICR/CD&lt;sub&gt;1&lt;/sub&gt; mice were infected with 200 &lt;i&gt;T. spiralis&lt;/i&gt; at 14, 56, 98 and 112 days preceding intravenous administration of 4 × 10&lt;sup&gt;6&lt;/sup&gt; viable BCG. Groups were tested for delayed hypersensitive foot pad responses 28 days following BCG inoculation. All mice receiving &lt;i&gt;T. spiralis&lt;/i&gt; and BCG exhibited a marked potentiation of the 24-hour foot pad response to Old Tuberculin over that shown by the appropriate controls.</jats:p