Feline Hybridoma Growth Factor/lnterleukin‐6 Activity

Ohashi, Takashi; Goitsuka, Ryo; Ono, Kenichiro; Hasegawa, Atsuhiko

An assay system was developed to measure feline hybridoma growth factor (HGF)/interleukin‐6 (IL‐6) activity in biological samples containing many kinds of cytokines by using the proliferation of the newly established mouse‐rat hybridoma clone. B3B1. The proliferative response of this B3B1 clone was IL‐6‐specific, and could not be promoted by other cytokines including IL‐1, IL‐2, IL‐3, and granulocyte‐colony‐stimulating factor (G‐CSF), The anti‐human B‐cell stimulatory factor 2 (BSF‐2)/IL‐6 antiserum did not neutralize feline HGF/IL‐6 activity in conditioned media prepared from feline con A‐stimulated splenocytes and unstimulated alveolar macrophages, indicating antigenic differences between species. Feline HGF/IL‐6 was eluted into the fractions corresponding to a molecular weight of 30,000–40,000 in gel filtration, and into the fractions at a salt concentration of 0.2–0.3 M NaCI in anion exchange chromatography. The physicochemical properties of feline HGF/IL‐6 were slightly different from those of murine and human IL‐6.