Presence of RSV in children with respiratory disease. (A) Detection of RSV-specific RNA. Collection of eye swabs and RT-PCR amplification of RSV F mRNA and "control" GAPDH mRNA segments were carried out as described under Methods. Only representative samples are shown. Lanes 1–4 = respiratory patients; 5,6 = healthy, uninfected individuals; 7,8 = same samples as 1 and 2, respectively, except that the RT reaction was not performed before PCR. (B) Presence of infectious RSV. Portions of the eye swab wash were added to HEp-2 monolayers to test for RSV growth as described under Methods. The lane numbers represent the same patient samples as in A. The P protein of RSV was detected by immunoblot; note that samples that contained viral RNA also contained infectious virus as judged by the intracellular synthesis of the P protein (lanes 1–4). (C) Syncytia in HEp-2 monolayers inoculated with samples #1 through 6 (the same numbers as in A and B). Note that samples that were RSV-positive (#1–4) in A and B formed syncytia, whereas RSV-negative samples (#5, 6) did not.