Pneumococcal population in the era of vaccination: changes in composition and the relation to clinical outcomes

Background: Vaccination of infants with pneumococcal conjugate vaccines (PCV) has resulted in major shifts in circulating serotypes. Aim: To investigate the impact of PCV7 on the clonal composition of the pneumococcal population, and the relation of clonal lineages and clinical outcome. Materials & methods: By using multiple-locus variable number of tandem repeat analysis, we assessed the pneumococcal populations before (n = 1154), 2-3 years after (n = 1190) and 4-6 years after (n = 1244) the introduction of PCV7 in The Netherlands. Results: We found statistically significant shifts in clonal lineages within serotypes 1 and 12F based on multiple-locus variable number of tandem repeat analysis results after the implementation of PCV7. Within serotype 12F, the increasing clonal lineage was significantly more associated with pneumonia. Conclusion: Shifts in clonal lineages within serotypes could impact the outcomes of pneumococcal disease and fill the niche of the vaccine serotype

Neonatal infection with a milk-borne virus is independent of β7 integrin- and L-selectin-expressing lymphocytes

Mouse mammary tumor virus (MMTV) is acquired by neonates through milk and first infects lymphocytes in Peyer’s patches. We show here that newborn mice lacking 7 integrin or Lselectin were infected with MMTV at wild-type levels in both their lymphoid and mammary tissues. Superantigen-mediated activation and cognate T cell deletion were also unimpaired in both types of null mice. A large proportion of neonatal Peyer’s patch lymphocytes in wildtype mice were 7 and 1 integrin low and both populations increased in response to MMTV infection. These results suggest that adhesion molecules other than 7 integrin or L-selectin play a role in lymphocyte homing in the gut, peripheral lymph nodes and mammary gland in response to MMTV infection.Fil: Czarneski, Jennifer. State University of Pennsylvania; Estados UnidosFil: Berguer, Paula Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Bekinschtein, Pedro Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Kim, David C.. State University of Pennsylvania; Estados UnidosFil: Hakimpour, Paul. State University of Pennsylvania; Estados UnidosFil: Wagner, Norbert. State University of Pennsylvania; Estados UnidosFil: Nepomnaschy, Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Piazzon, Margarita Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Ross, Susan R.. State University of Pennsylvania; Estados Unido