CROSSREACTIVE ANTIBODIES AND MEMORY T CELLS TO HUMAN AND ZOONOTIC INFLUENZA A VIRUSES IN VOLUNTEERS

Abstract

There exists a real hazard of transferring zoonotic influenza A viruses, either swine, or avian, into human population. In such case, severity of such pandemics depends on the pathogen-specific immunity in the population. Virtual absence of such immunity in humans was declared in the literature. In this work, we assessed systemic, local, and T-cell immunity to potentially pandemic H3N2sw, H5N1, H5N2, H7N3, H7N9 and H2N2 influenza A viruses in a group of healthy adults of different age. Our results indicate that these subjects develop the following immune reactions: (i) local (i.e., nasal IgA) and cellular (CD4+ and CD8v memory T cells) heterosubtypic immunity, in absence of detectable virus-specific serum antibodies to avian influenza A viruses; (ii) Local immune responses (as nasal IgA) to human A (H2N2) virus which circulated in 1957-1968 were detected both in subjects who could be primed at that time, but also in subjects born after 1968; (iii) full-scale systemic and local immunity to potentially pandemic А (H3N2sw) swine virus was found in the group. Conclusion. In order of proper epidemiological forecasts and planning appropriate preventive measures for potentially pandemic Influenza A viruses, a regular monitoring of collective immunity should be performed using different adaptive markers. In this respect, any conclusion based on molecular analysis only could lead to considerable mistakes, and should be accomplished by the mentioned immunological studies.

Keywords

• influenza virus
• live vaccine
• immunization
• heterosubtypic immunity