They respond to protect themselves in a variety of ways. Humoral Antibody response mediated by B cells. Takes a couple of weeks,antibodies binds to both virus and virus infected cells. IgM, IgA, IgG, IgD, IgE. Different types with different functions.
Antibodies are proteins, which recognise molecular shapes or epitopes known as antigens.
Antibodies show tremendous diversity. Self recognition antibodies are screened out during development. Direct binding of an antibody to a virus has various consequences. This response is slow. If memory cells are present then it is much faster.