Ci. Baldwin et Da. Denham, ISOLATION AND CHARACTERIZATION OF 3 SUBPOPULATIONS OF IGG IN THE COMMON CAT (FELIS-CATUS), Immunology, 81(1), 1994, pp. 155-160
Although the cat is an important model for a number of human diseases
little is known of its basic humoral immunity. In this study we have i
solated three subpopulations of IgG from cat serum by DEAE anion-excha
nge chromatography and protein A affinity chromatography. Subpopulatio
n 3 did not bind to DEAE equilibrated in 2 mM phosphate buffer pH 8.0
while subpopulations 1 and 2 were eluted, as a mixed population, with
a salt gradient between 3 mM and 25 mM. When this fraction was loaded
onto protein A-Sepharose two distinct peaks were always generated in a
pH gradient (pH 8.0-2.1). The first of these, subpopulation 2, was el
uted on average at pH 4.3 while the second, subpopulation 1, was elute
d on average at pH 3.4. Subpopulations 1 and 2 had similar immunoelect
rophoretic mobilities and isoelectric points while subpopulation 3 was
more cathodic in both tests. Antisera produced in both mice and rabbi
ts were rendered specific, by absorption of crossreacting antibodies,
for determinants on the heavy chain of each subpopulation as shown by
Western blotting. The data suggest, but are not conclusive, that each
of these subpopulations are distinct subclasses of IgG.