Serum levels of conglutinin, complement, and immunoconglutinin in cattle infected with Anaplasma marginale.

: Sera from 10 splenectomized yearling cattle given massive doses of Anaplasma marginale (peracute cases) were assayed for conglutinin and complement. Sera from 5 nonsplenectomized yearling cattle given smaller doses (acute cases) were assayed for conglutinin, immunoconglutinin, and complement. In the peracute cases, conglutinating activity disappeared within 6 days after the cattle inoculated. In the acute cases, conglutining began to disappear at 3 weeks after inoculation and had disappeared at peak parasitemia at 4 weeks. Conglutinin returned by 7 weeks after inoculation. In the same acute cases, immunoconglutinain appeared at 6 weeks after inoculation and then slowly disappeared. The complement levels in the peracute and acute cases did not change appreciably.