Sentence:  After passing * * f through DEAE-cellulose , the titer of <WSD>antibodies</WSD> to WTV in the specific fraction was 1 : 4 of the titer before such passage ( precipitin ring tests by R. F. Whitcomb ) ; but mere dilution of the conjugate to 1 : 4 did not satisfactorily remove nonspecific staining . 
Meaning of the word marked with <WSD> tags:  any of a large variety of proteins normally present in the body or produced in response to an antigen which it neutralizes, thus producing an immune response