A murine model system was established to study immune responses to the Pnu-Imune vaccine, which is made up of 23 different pneumococcal capsular polysaccharides. In this animal model, antibody-forming cell responses to 21 of 23 individual polysaccharides in the vaccine were detected. The Pnu-Imune vaccine elicited good antibody responses from the spleens and mesenteric lymph nodes (MLN) of young mice, whereas a variety of other peripheral lymph nodes were unresponsive. The immunoglobulin M plaque-forming cell (PFC) response in the spleen to the Pnu-Imune vaccine (given intraperitoneally or subcutaneously) decreased dramatically with increasing age. However, the spleen and MLN differed in their susceptibility to an age-associated decline in immune function. While the PFC responses in the spleen declined with age, the PFC response in the mucosa-associated MLN did not decline with age but instead remained constant over the entire age span of 4 to 28 months studied. These studies showed that the spleen, peripheral lymph nodes, and MLN did not demonstrate parallel age-associated defects in antibody responses to pneumococcal polysaccharides when the antigen was administered systematically. Also, the deficient splenic antibody response to Pnu-Imune vaccine in aged mice could be enhanced by injecting a combination of Pnu-Imune vaccine and the nontoxic adjuvant monophosphoryl lipid A. Moreover, an immunoglobulin G response was induced when the immunogen was a mixture of vaccine and adjuvant.
This work was supported in part by NIH grants AI-21490 and AG-05731, funds from the Tobacco and Health Research Institute of University of Kentucky and from the Kentucky Thoracic Society, and Research Career Development Award K04AG00422 to Bondada Subbarao.
Garg, Manju and Bondada, Subbarao, "Immune Responses of Systemic and Mucosal Lymphoid Organs to Pnu-Imune Vaccine as a Function of Age and the Efficacy of Monophosphoryl Lipid A as an Adjuvant" (1992). Microbiology, Immunology, and Molecular Genetics Faculty Publications. 115.