Claims for Patent: 4,806,346

Summary for Patent: 4,806,346

Title:	Method for isolation of antigen specific immunoglobulin
Abstract:	A process for preparing the purified F(ab).sub.2 fragment of equine Ig(T) from horses hyperimmunized with snake venom which comprises: (a) passing crude diluted hyperimmune equine serum contianing snake venom antigen specific Ig(T) buffered to an acidic pH through a strong base anion exchange polymer; (b) passing the resultant pass-through solution to which is added sodium chloride to a concentration of 0.05-0.124M through a strong acid cation exchange polymer; (c) adjusting the pH of the pass-through of step (b) to a pH of 3.3, and digesting said pass-through with pepsin; and (d) ultrafiltering said pepsin-digested pass-through to obtain purified F(ab).sub.2 fragment of the snake venom antigen specific equine Ig(T).
Inventor(s):	Hum; Wah-tung (Jeffersonville, PA), Lee; Shaw-guang (Villanova, PA)
Assignee:	American Home Products Corporation (New York, NY)
Application Number:	06/942,313
Patent Claims:	1. A process for preparing the purified F(ab).sub.2 fragment of equine Ig(T) from horses hyperimmunized with snake venom which comprises: (a) passing crude diluted hyperimmune equine serum containing snake venom antigen specific Ig(T) buffered to an acidic pH through a strong base anion exchange polymer; (b) passing the resultant pass-through solution to which is added sodium chloride to a concentration of 0.05-0.125M through a strong acid cation exchange polymer; (c) adjusting the pH of the pass-through of step (b) to 3.3, and digesting said pass-through with pepsin; and (d) ultrafiltering said pepsin-digested pass-through to obtain purified F(ab).sub.2 fragment of the snake venom antigen specific equine Ig(T). 2. The process of claim 1, wherein the hyperimmunized equine serum is derived from horses hyperimmunized with a combination of venoms derived from Crotalus adamanteus, C. atrox, C. terrificus and Bothrops atrox. 3. The process of claim 1, wherein said crude hyperimmune serum is diluted 5-10 times with acetate buffer to a pH of about 5.0. 4. The process of claim 1 wherein said strong base anion exchange polymer is diethylaminoethyl cellulose. 5. The process of claim 1, wherein said strong base anion exchange pass-through is salinized to a sodium chloride concentration of 0.08M. 6. The process of claim 1, wherein said strong acid cation exchange polymer is sulfopropyl dextran. 7. The process of claim 1, wherein said strong acid cation exchange polymer pass-through is adjusted to a pH of about 3.3 with acetic acid. 8. The process of claim 1, wherein the strong acid cation exchange polymer pass-through is digested with pepsin for about 16 hours at 37.degree. C. 9. The process of claim 8, wherein said pepsin is used at a concentration of 0.05% on an enzyme to substrate basis. 10. The process of claim 1, wherein said ultrafiltration is carried out using a hollow fiber filter having a molecular weight cut-off of 50,000-75,000. 11. The process of claim 1, wherein said strong base anion exchange polymer is regenerated using 1M sodium chloride followed by equilibration in acetate buffer. 12. The process of claim 1, wherein said strong acid cation exchange polymer is regenerated by washing with 1.0M sodium chloride followed by equilibration in acetate buffer. 13. The process of claim 1, which is carried out continuously on regenerable ion exchange polymer columns. 14. A process for preparing the purified F(ab).sub.2 fragment of equine Ig(T) from horses hyperimmunized with snake venom which comprises: (a) passing crude hyperimmune equine serum, containing snake venom antigen specific Ig(T) buffered to a pH of about 5.0 with acetate buffer, through a strong base diethylaminoethyl-cellulose anion exchange column; (b) passing the resultant pass-through solution, to which is added sodium chloride to a concentration of about 0.08M, through a strong acid sulfopropyl dextran cation exchange column; (c) adjusting the pH of the pass-through of step (b) to about 3.3 with acetate buffer, and digesting said pass-through with 0.05% pepsin for 16 hours at 37.degree. C.; and (d) ultrafiltering said pepsin-digested pass-through using a hollow fiber filter having a molecular weight cut-off of 50,000-75,000 to obtain purified F(ab).sub.2 fragment of the snake venom antigen specific equine Ig(T). 15. A snake envenomation antivenin comprising the purified F(ab).sub.2 fragment of equine Ig(T) from horses hyperimmunized with snake venom prepared by the process of claim 1 and a pharmaceutically acceptable carrier. 16. The antivenin of claim 15, which is lyophilized and reconstitutable for parenteral administration.

Details for Patent 4,806,346

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Merck Sharp & Dohme Corp.	LACTRODECTUS MACTANS	antivenin (latrodectus mactans)	For Injection	101062	02/13/1936		2040-01-27