Botrocetin agglutination of rat megakaryocytes: a rapid method for megakaryocyte isolation.

Botrocetin isolated from the venom of Bothrops jaracara has been shown by others to induce binding of von Willebrand Factor to glycoprotein Ib and thereby produce platelet agglutination in a wide range of animal species. We have found that botrocetin also facilitates the agglutination of megakaryocytes and have used this property to develop a method to isolate megakaryocytes from rat bone marrow. When botrocetin is added to a mixture of rat bone marrow, rat platelets, and rat plasma, coagglutination of megakaryocytes and platelets occurs. The agglutinated complexes, containing > 95% of the megakaryocytes, may then be separated from the remaining marrow cells by filtration. Megakaryocytes account for 39% (range 30%-48%) of the isolated cells and 83% (range 77%-88%) of the isolated cell mass. This method allows the virtually complete removal of megakaryocytes from bone marrow as well as their isolation to a high degree of purity. It should provide a useful, inexpensive, general method for the rapid isolation of megakaryocytes from multiple, small marrow samples from a wide range of species.