Characterization of a guinea-pig lymphokine, macrophage agglutination factor

We have previously shown guinea-pig macrophage agglutination factor (MAggF-) to be a high mol. wt (greater than or equal to 150,000) T-cell-dependent lymphokine that is antigenically distinct from migration inhibition factor and immunoglobulin. As part of an ongoing project to purify and isolate this material, we have determined a number of its physical and chemical characteristics in culture supernatants of lymph node cells. MAggF is stable in the pH range 3-9, is stable to heating at 56 degrees for 30 min, but undergoes denaturation after heating at 60 degrees--65 degrees. MAggF activity is destroyed by proteinase but is resistant to treatment with hyaluronidase. MAggF activity is lost on reduction and is not regained on prolonged dialysis. Preparative isoelectric focusing of culture supernatants showed MAggF in a single broad peak (pI 5.6-6.3), with maximum activity at pI 6.1.