EQUINE MONOCYTE-DERIVED MACROPHAGE CULTURES AND THEIR APPLICATIONS FOR INFECTIVITY AND NEUTRALIZATION STUDIES OF EQUINE INFECTIOUS-ANEMIA VIRUS

Equine infectious anemia virus (EIAV) has been shown to infect cells o f monocyte;macrophage lineage. These primary cells are intrinsically d ifficult to obtain; to purify and to culture in vitro for extended per iods of time. As a result, most in vitro studies concerning this lenti virus make use of primary equine fibroblasts or transformed canine or feline cell lines. We describe methods that yield reproducibly pure cu ltures of equine blood monocytes from peripheral blood mononuclear cel ls. The in vitro differentiation of these cells into mature equine mac rophage was verified using various cytochemical staining methods. The equine monocyte-derived macrophage (MDM) cultures were found to replic ate cell-adapted and field strains of EIAV more efficiently than cultu res of fully differentiated equine splenic macrophage. Having establis hed reproducible and fully differentiated cultures of equine macrophag e, in vitro assays of virus infectivity and serum neutralization were developed using the in vivo target cell of EIAV. These procedures, whi le developed for the EIAV system, should be equally useful for in vitr o cultures of other macrophage-tropic pathogens of horses. (C) 1998 El sevier Science B.V. All rights reserved.