Antigenic complex from N. gonorrhoeae

A method of obtaining an antigenic, immunogenic, complex obtained from the cell surface of N. gonorrhoeae which is protective against N. gonorrhoeae having a molecular weight of from about 9,200,000 to about 9,500,000, over 80% of the complex being formed of five sub-units in approximately equal amount having molecular weight of about 68,000, about 50,000, about 34,000, about 27,000 and about 10,500, the complex containing a dry weight basis from about 90 to about 95% protein, up to about 7% lipopolysaccharide, about 2% carbohydrate and less than 1% of RNA, DNA and phospholipids which comprises stirring a homogenized cell paste of N. gonorrhoeae for from about 10 to about 15 hours, removing cellular debris, RNA and DNA from the homogenized extract, and separating a fraction having a molecular weight in excess of about 9,000,000.