Feline leukemia virus is part of a family of viruses called Retroviridae. It consists of a protein core and a single-stranded ribonucleic acid surrounded by a lipoprotein envelope. The basic structure of FeLV is shown below: it consists of an outer envelope and an inner capsid.
are four different subtypes of the gamma retrovirus
FeLV:FeLV-A,FeLV-B, FeLV-C,and FeLV-T.Variation of the
major envelope protein, gp70, is associated with
the 3 virus sub-groups A, B and C. All cats
infected with FeLV-B, FeLV-C, and FeLV-T are co-infected with FeLV-A,
with FeLV-A being the only type that is transmitted between animals.
The other subtypes influence the clinical expression of
disease - FeLV-B may accelerate damage to nerve tissue and lymphoma (a
cancer of the lymphatic cells in the immune system such as
B-lymphocytes, which are important for antibody production, and
T-lymphocytes, important for
cells); FeLV-C is associated with
non-regenerative anemia (a form of anemia where cats cannot replace
red blood cells with new ones); and FeLV-T is associated
immunodeficiency in cats. The envelope protein,
pl5e, which is anchored in the plasma
membrane of infected cells, appears to be at least partially
responsible for the
viral-induced immunosuppression. Antibody to
gp70, which is expressed on the outer surface of the virus as well as
on the surface of infected
cells,is important in natural resistance.
Anderson et al., 2000; Anderson et al., 2001; Essex, 1980; Hardy, 1980; Keel et al., 2008; Ogilvie et al., 1988; Sykes, 2010