Two-dimensional separation of human body fluid proteins.

High resolution protein patterns of various human body fluids are compared. They were obtained by non-restrictive agarose electrophoresis in the first and exclusion electrophoresis on polyacrylamide pore gradients in the second dimension. The majority of serum proteins above 10 mg/dl have been identified and the heterogeneities of high density lipoproteins, immunoglobulins and haptoglobins become visible within the charge/size grid of the two-dimensional pattern. Since secretory and serum-derived components can be differentiated, the contribution of protein synthesis and filtration to the formation of the finally released fluid can be assessed. The technique may be used to screen complex soluble protein mixtures for pathological components. There is a wide range of variations in composition from the secretory fluids (e.g. tears, colostrum, milk, seminal fluid) to virtually "pure" filtrates (pleural effusions, osteoarthritic synovial fluid, cyst puncture fluid, and amniotic fluid). It is evident that the composition of the serum-derived fraction depends primarily upon the selectivity of the respective blood/body fluid barriers. The resolution capacity of the technique is compared with that obtained by two-dimensional gel-focusing/SDS electrophoresis of the constituent serum protein subunits.