Procomplementary Activity of Swine Serum and Its Elimination With Periodate Treatment

Solid-phase radioimmunoassay techniques for the detection of African swine fever antigen and antibody

“…The 100 % inhibition of iodinated antibody attachment to the plate was measured in wells receiving a 1/5 dilution of standard antiserum, whereas the 0 % inhibition was measured in wells without competing antiserum. The % inhibition at any serum dilution was then calculated from the formula below: (Akao et al 1962) and IEOP using the assay of Pan, DeBoer & Hess (1972). ASFV antibody titres from ten pigs which had either died or recovered from infection with different ASFV isolates were compared using RIA techniques and the CF and IEOP tests.…”

Improving a Complement-fixation Test for Equine Herpesvirus Type-1 by Pretreating Sera with Potassium Periodate to Reduce Non-specific Hemolysis

“…However, in some sera, inhibition of hemolysis is incomplete, even though virus-specific antibodies appear to be present. Non-specific hemolysis during CF testing has also been reported in swine influenza and other infectious diseases of swine [1,2,3, 8]. In these studies, one factor in swine sera that enhances the hemolysis caused by guinea pig complement was identified and named as procomplementary factor (PCF).…”

“…PCF is present in 89.5% of swine sera and is not inactivated by heating for 30 min at 56°C, the conditions under which CF testing is generally performed [2, 5]. PCF activity of PCF is effectively diminished by treatment of the sera with 0.01 M potassium periodate (KIO 4 ) for 1 hr at 37°C, and this method has been employed in CF tests for swine influenza and swine enzootic pneumonia [1, 8]. Here, we examined sera from horses in the field using a conventional CF test for EHV-1 to determine the incidence of non-specific hemolysis.…”

“…Next, we performed CF testing with sera pre-treated with KIO 4 in accordance with the method reported by Akao et al [1]. Briefly, 100 µl of serum were incubated for 30 min at 56°C.…”

“…Phenol or formalin treatment and reduction in pH are effective at reducing procomplementary activity [3,4,5]. However, a slight decrease in CF titers after treatment with phenol or formalin has been reported [1, 9]. Although pH reduction does not affect the titer, this method requires overnight incubation [3].…”