Quantification of lymphocytic choriomeningitis virus with an immunological focus assay in 24 well plates

Abstract

Titres of lymphocytic choriomeningitis virus (LCMV) were determined on adherent fibroblast cell lines in 24, respectively 96 well plates. After absorption of virus by cells and 48 h incubation under a methylcellulose overlay, cell monolayers were fixed with 4% formaldehyde in phosphate buffered saline, permeabilized by incubating in 0.5% Triton X-100 in balanced salt solution and then stained with a monoclonal rat anti-LCMV and a peroxidase labeled second stage antibody. The sensitivity of the assay is within a factor of 2-4 of conventional plaquing methods. The method is quicker (2-3 days), as compared to conventional methods (4-6 days) and less expensive with respect to both workhours and materials involved. The method also detects poorly- or non-plaquin LCMV isolates, and therefore drastically reduces the needs for titration of LCMV in mice.