light chains and blood grouping and PAGE

[ashokprabhus]

1.how to distinguish/separate between two light chains of immunoglobulins as they are similar in all respects-ie., they move as asingle band in SDS-PAGE

how do we know on the 1st hand that 2subunits of light chain are there in the same band

2.why and how does a A+ve person have Anti-B-antibody in his sera even without prior exposure to B antigen

3.why dont we use urea in place of sds in doing PAGE?

[JackMuChabas]

They do not move in single bans but move in a sub page of diaslectic immune responders.