Characterisation of lymphocyte migration following influenza virus infection in order to assess vaccine efficacy

The aim of this study was to characterise lymphocyte cell population trafficking throughout the mucosal immune system following influenza virus infection. This information will be used as a "gold standard" to investigate the efficacy of a DNA vaccine candidate. Virus-specific immune responses were quantitated in terms of specific antibody and CD8(+) T cell frequency and distribution of response. Initial ELISA results demonstrated an IgG isotype-dominated response throughout the mucosal immune system predominantly seen in the mediastinal lymph node (MedLN). The IgA response observed in the MedLN was 70-100% virus-specific while the IgG response was an average of 20% virus-specific. Time point analysis showed initial virus-specific antibody produced in the MedLN and spleen, which spread to the lungs and nasal associated lymphoid tissue (NALT) and began to wane after day 21. Initial ELISPOT results following influenza infection demonstrated a mesenteric LN response perhaps indicating a wave of virus-specific CD8(+) T cells circulating throughout the mucosal immune system. Interestingly, DNA immunisation with plasmid expressing influenza nucleoprotein also produced a virus-specific T cell response in the NALT. It is hoped that this study will elucidate information regarding the common mucosal immune system and determine biological markers that correlate to vaccine efficacy. (C) 2004 Elsevier B.V. All rights reserved.