If the antibody is directed at a component of exosomes and this component is reasonable specific for exosomes, this should be possible in principle. Try to incubate your sample with the beads o/n on an end-over-end mixer in the cold room. Then wash and see what you pulled down. The washing buffer is critical: too denaturing and you loose exosomes, too gentle and you get a lot of irrelevant material. Mixtures of PBS with desoxycholate and/or SDS are commonly used in such cases.

Hello,

You may look at the following work:

Blood diffusion and Th1-suppressive effects of galectin-9–containing exosomes released by Epstein-Barr virus–infected nasopharyngeal carcinoma cells

Jihène Klibi et al. Blood 2009 113:1957-1966