MABs with immunosuppressant activity currently authorised for MS are alemtuzumab, natalizumab, ocrelizumab, ofatumumab and ublituximab. They principally target T and B cells.¹¹

Alemtuzumab binds to T and B lymphocytes. Its effects in MS may include causing a reduction and then repopulation of lymphocytes with increases in the proportion of regulatory T cells, memory T and B cells, as well as having effects on other lymphocytes including neutrophils, macrophages and natural killer (NK) cells. This can reduce the potential for disease relapse and delay disease progression.

Natalizumab is described as a selective adhesion-molecule inhibitor. It binds to leukocytes, stopping activated T cells from crossing the blood-brain barrier. Disrupting the process may lead to reduced inflammation in the brain and CNS and stop further immune cells from infiltrating an inflamed site reducing the formation or enlargement of MS lesions.

Ocrelizumab selectively targets B cells expressing CD20, a cell surface antigen. Its activity in MS is thought to be immunomodulatory and derives from a reduction in number and activity of these types of B cells. Ofatumumab targets CD20 B cells causing them to break down. It also can deplete T cells which express CD20. Ublituximab also targets CD20-expressing B cells.