Reduction of complement activation through an alteration of the Fc fragment of immunoglobulins by <FONT FACE="Symbol">b</font>-propiolactone treatment was carried out in equine antisera raised against rabies virus, Bothrops venoms and diphtherial toxin. Results were evaluated by means of an anaphylactic test performed on guinea-pigs, and compared to the ones obtained with the same sera purified by saline precipitation (ammonium sulfate), followed or not by enzymatic digestion with pepsin. Protein purity levels for antibothropic serum were 184.5 mg/g and 488.5 mg/g in <FONT FACE="Symbol">b</font>-propiolactone treated and pepsin-digested sera, respectively. The recovery of specific activity was 100% and 62.5% when using antibothropic serum treated by<FONT FACE="Symbol"> b</font>-propiolactone and pepsin digestion, respectively. The antidiphtherial and anti-rabies sera treated with <FONT FACE="Symbol">b</font>-propiolactone and pepsin presented protein purity levels of 5,698 and 7,179 Lf/g, 16,233 and 6,784 IU/g, respectively. The recovery of specific activity for these antisera were 88.8%, 77.7%, 100% and 36,5%, respectively. <FONT FACE="Symbol">b</font>-propiolactone treatment induced a reduction in complement activation, tested "in vivo", without significant loss of biological activity. This treatment can be used in the preparation of heterologous immunoglobulins for human use.
Heterologous antisera; Complement activation; <FONT FACE=Symbol>b</font> propiolactone; Antisera
