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In a group of 22 patients with second and third degree burns, seven were found to have impaired chemotaxis. The chemotactic defect was present from two to 68 days and eventually became normal. The impairment was found to be due to a primary transient defect in polymorphonuclear leukocytes and not to an inhibitor or inactivator in the serum.

Immunization of New Zealand White rabbits with purified visna virus elicited antibody activity demonstrated by passive hemagglutination (PHA), complement fixation (CF), and indirect immunofluorescent tests. The antibody activities of hyperimmune sera and Sephadex G-200 fractions of the sera were studied. It was found that the PHA test was 10 to 100 times more sensitive than the CF test in detecting visna antibodies in rabbits. It was also found that the immunoglobulin M fractions from Sephadex G-200 filtration displayed greater PHA activity than did the immunoglobulin G fractions. Although neutralizing antibody was demonstrated in the serum of the natural host (sheep), our attempts to demonstrate neutralizing antibody in the sera from hyperimmunized rabbits (non-natural host) so far have failed.In its natural host, the sheep, visna virus causes the formation of neutralizing (9) and complement-fixing antibodies (1) and of antibodies detectable by fluorescein labeling (2, 11). On the other hand, there have been no reports of successful hyperimmunization of other animal species with visna virus. In fact, several attempts to inoculate small laboratory animals with the virus have given negative results, since proliferation of virus or antibody response could not be detected (H. Thormar, unpublished data).In the present study, rabbits were hyperimmunized with visna virus by using repeated injections of high concentrations of purified virus. Complement fixation (CF) test and immunofluorescent techniques were employed for demonstration of an antibody response. In addition, the passive hemagglutination (PHA) test was shown to be a sensitive method for assay of antibodies against visna virus.MATERIALS AND METHODS Virus. Visna virus strain K796 in its 17th tissue culture passage was used for immunization of rabbits and as antigen in serological tests. The virus was grown in monolayer cultures of sheep choroid plexus cells, as previously described (4). Infectious tissue culture fluid was harvested, and the virus was concentrated and purified by the method described by Lin and Thormar (5). Before use, the purified virus suspension was dialyzed against 0.15 M phosphate-buffered saline (PBS) at 4 C overnight. The titer of the final virus preparation used for immunization was 109 50% tissue culture infectious doses (TCID5o) per milliliter.Antisera. New Zealand White rabbits (5.0 to 6.0 lb.) were given 1 ml of primary intravenous injection of virus. On days 7, 14, 22, 36, 50, 64, 78, and 92, they received intramuscularly 2 ml of a mixture of virus and complete Freund's adjuvant. Ten days after the last inoculation, blood was collected via heart puncture. The sera were separated from the whole blood, placed in vials, and stored at -20 C. Antisera against a homogenate of normal choroid plexus cells and against bovine serum albumin were prepared in the same manner. Unless otherwise stated, all sera used in PHA and CF tests were inactivated at 56 C for 30 min and absorbed with washed sheep red blood cells (RBC) until no hemagglutin...

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