SELPLG and lentivirus infection: It is important to remember that PSGL-1, like other HIV restriction factors, conforms to important characteristics such as (i) induction by interferons [26], (ii) response to lentivirus infection by significant production of its amino acid sequences [27], and (iii) having its activities countered by lentivirus (in the case of HIV infection, Vpu and Nef are essential to countering PSGL-1 activities).