Variation in simian immunodeficiency virus env V1 region in simian AIDS-Associated lymphoma

Genetic variation of SIV env during the course of infection provides a larg e population pool that is continually shaped by selective forces in vivo an d may influence the development of clinical disease, SAIDS-associated lymph oma (SAL) in the SIV-infected macaque is typically a clonal or oligoclonal mass of B cell origin, extranodal in anatomic distribution, in which SIV is restricted largely to infiltrating macrophages. To explore the degree of g enetic variation in SIV env represented in SAL, a 480-bp DNA fragment conta ining the V1 region was PCR amplified from seven cases of SAL and from a no nneoplastic lymph node of an SIV-infected macaque, The nucleotide sequence of the V1 region was determined from at least 10 clones from multiple indep endent amplification reactions of each tissue. Overall, the degree of V1 va riability within lymphomas was found not to be restricted but to resemble t he heterogeneity reported in SIV-infected lymphoid and other tissues, V1 va riation in the nonneoplastic lymph node was unexpectedly limited, perhaps r elated to the unusual disease condition associated with SAIDS in that anima l. Unlike observations from SIV-infected tissues of animals without neoplas tic disease, no increase was detected in the number of O- or N-linked glyco sylation sites in the V1 regions isolated from lymphomas as compared with t he original inoculum, These findings suggest that, within the microenvironm ent of the lymphoma, the immune evasion conferred by increased glycosylatio n may offer little selective advantage.