Letter | Published:

Proteins Susceptible to Cold in Pathological Sera

Nature volume 149, page 528 (09 May 1942) | Download Citation



IN the blood of dogs infected with kala-azar, proteins are precipitated on cooling to room temperature (20° C), or better still when allowed to stand in the ice-box (5° C.) overnight. This protein belongs to the pathologically increased euglobulin fraction. In twenty-one sera investigated (six cases) the cold fraction test was positive. In typical specimens, turbidity soon followed by precipitation sets in within a quarter of an hour of standing in the ice-box. The protein precipitated from kala-azar serum on cooling (cold fraction) is defined as the centrifugable protein fraction which precipitates after 24 hr. at 5°C, and is redissolved by warming to37°–50°C. This cold fraction ranged between traces of turbidity which could not be determined quantitatively to maximal 3 gm. per 100 c.c. of serum. Typical cases gave tests as shown in the accompanying table:

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  1. Department of Pathological Physiology, Hebrew University, Jerusalem.

    • L. STEIN
    •  & E. WERTHEIMER


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