Vaccines oben coetain agents derived from the surface proteins of foreigs pathegens that cause discase. These agents stimulate the immune system of the host, allowing the host to recognize and destroy the puthogen in any future encounters. However, Some pathogens have developed mechaniums to alter their surface proteins and evade the immune system, making is difficult or Impossible to develop effective vaccines against them.
How do matations that affect the viral protein coat allow human immusodeficiency virus (III) to evade the immune system?
â—» The virus alters the viral protein coat to mimic hout cells.
â—» Mutant viral coat proteins attract macrophages to the pathopen.
â—» Matations can alter the antigenic determinant on the protein coat.
â—» Changes to the viral peotein coat enable the bound virus to lowe the antigen-binding site.
A protoman called Thpanosoma brucei, carried by the tsetse ff), causes African sleeping sickaess. Owe variable surface Dyooprotein (VSO), or surface coat protein, dominates the trypanosome surface. The trypanosome genome encodes over to, different versions of VSOs. All of the celis in an intial infoction feature the same VSG coat on their surfaces, and the immane system readily recognizes this proteis as foreign.
However, an individual trypanosome cell in the broader population will witch and randomly begin capressing a different variant of the VSG coat. All the descendants of that cell will have the new and different protein on their surface. As the populatios with the second VSO cout increases, an individual cell will then switch to a thind VSG coat, and so on.
