Restricted species tropism of maedi-visna virus strain EV-1 is not due to limited receptor distribution.

The distribution of receptors for maedi-visna virus (MVV) was studied using co-cultivation assays for virus fusion and PCR-based assays to detect the formation of virus-specific reverse transcription products after virus entry. Receptors were present on cell lines from human, monkey, mouse, chicken, quail, hamster and ovine sources. Thus, the distribution of the receptor for MVV is more similar to that of the amphotropic type C retroviruses than to that of other lentiviruses. The receptor was sensitive to proteolysis by papain, but was resistant to trypsin. Chinese hamster ovary (CHO) and lung cells (V79 TOR) did not express functional receptors for MVV. The receptor was mapped to either chromosome 2 or 4 of the mouse using somatic cell hybrids. This allowed several candidates (e.g. MHC-II, CXCR4) that have been proposed for the MVV receptor to be excluded.