Untitled - D Ank Unlimited

influenza virus immunity 390 influenza virus immunity
Influenza virus.
HA
NA
PB2 PB1PA NP
Influenza A subtype N2 neuraminidase (sialidase). A/Tokyo/3/67.
M1
0
nm
M2
NS 1 and NS 2
50
Influenza B/LEE/40 neuraminidase (sialidase).
the NA are in a central cavity encircled by two antigenic
sites. Influenza A viruses undergo variability that includes
antigenic drift, which yields variants of contemporary
epidemic strains that are sufficiently different to avoid
neutralization by antibody. The more extensive antigenic
shift may be a consequence of dual infection with human
and animal influenza A viruses. This can lead to the
development of a novel pandemic strain for which humans
have no preexisting antibodies. CD8 + virus-immune
cytotoxic T lymphocytes can clear influenza A virus from
infected lungs. It is necessary for the effector lymphocyte
to come into direct contact with the virus-infected target
cell. Immune CD4 + T lymphocytes are involved in lung
consolidation in influenza pneumonia and have a significant
role in clearance of the virus. CD4 + T cells facilitate
antibody production. They also facilitate the generation
of “helper cytokines” such as interleukin-4 (IL4) and
IL5 that promote clonal expansion and differentiation of