elution with various concentrations of sodium chloride in tris-hcl buffer ( ph 8.0 , 0.01 m ) resulted in fractions that were rich in either secretory immunoglobulin a ( siga ) ( 0.1 m nacl ) or free secretory component ( sc ) ( 0.05 m nacl ) .
C0020838
secretory immunoglobulin a
C0036538
secretory