HIV and Influenza Flashcards
why does the infection of CD4 T-cells destroy humoral immunity / what opportunistic pathogen is the main killer of hosts with AIDS
naive B cells can no longer be activated so antibodies can no longer be made / Tuberculosis
why can we not cure an HIV infection
it integrates into the cell DNA - no way to excise it back out (permanent infection for that cell) AND it is the most rapidly evolving pathogen known (changes with extreme speed) AND it stays ahead of the natural immune response
what is a quasispecies / why is HIV a quasispecies
a species with extreme diversity in a single host / all single and some souble mutants of HIV at each amino acid position encoded by the virus can be simultaneously found in the host each day
what therapy works to help slow down HIV
combinatory therapies - involves using two antibiotics that work in different ways because it is very unlikely that there is a mutated HIV that has a mutation to both of the antibiotics
what is the mutation in the human genome that makes them immune to HIV / why is this mutation thought to have occurred
a 32-nucleotide deletion in the CCR5 gene which renders it nonfunctional - HIV can no longer bind to it (bone marrow transplants of a homozygous immune donor has cured two HIV patients) / viral infection such as smallpox or hemorrhagic virus
what do endogenous retroviruses (ERVs) retain / what are they called when they are decayed by mutation
the three main retroviral genes / retroelements or retrotransposons
what do retrotransposons do
they cannot make a virus particle but can make genes that move around to integrate somewhere else in the genome
what has ERVs done to the human genome / what have human cells evolved to do
now occupies about 35% of the human genome / we have evolved to use some of these retroviruses (such as human endogenous retrovirus - W (HERVW) that is super important for placental fusion in eutoro)
how many different types of influenza is there / which three types can infect humans
4 - A, B, C, D / A (can cause global pandemic), B, and C (very mid disease caused)
what are some key features of influenza
the segmented genome into eight separate parts of RNA the loose containment of RNA genome in shell of matrix proteins, the coating of RNA segments in nucleocapsid proteins, the two major envelope proteins (HA and NA)
why can influenza A cause a horrific global pandemic
because it can infect the most species and pandemics are associated with when a virus jumps from a species to a new species
what is the key receptor for influenza entry into a host cell
Hemagglutinin (HA) - binds to sialic acid proteins on cells surface - causes endocytosis when bound - drops pH of the host which leads to a conformational change in HA which causes membrane fusion - RNA and proteins are now in cytoplasm
why are we worried about the deadly influenza in aquatic birds
because if it infects our chickens and undergoes an antigenic shift that allows it to infect humans a global pandemic will likely occur
what dictates which species influenza can infect / which ones are humans infected by
the HA and NA / we are infected by H1, H2, and H3
