Multiple sclerosis-associated agent: neutralization of the agent by human sera

Area of Science:

• Neuroimmunology
• Virology
• Epidemiology

Background:

• Multiple sclerosis (MS) is a chronic neurological disease.
• The potential role of infectious agents in MS etiology is under investigation.
• The MS-associated agent (MSAA) has been implicated but requires further validation.

Purpose of the Study:

• To investigate the presence and activity of MSAA-neutralizing antibodies in individuals with and without MS.
• To explore the association between MSAA and MS.
• To determine if MSAA is an etiological factor in MS.

Main Methods:

• Sera and cerebrospinal fluids from diverse populations were tested for neutralizing activity against MSAA.
• MSAA induces polymorphonuclear leukocyte (PMN) depression in experimental animals.
• Neutralizing activity was localized to immunoglobulin fractions, indicating antibody involvement.

Main Results:

• A significant proportion of sera from MS patients, their relatives, and East African donors showed MSAA-neutralizing activity.
• Only one serum from US donors without MS contact exhibited neutralizing activity.
• Neutralizing antibodies were found in cerebrospinal fluid of MS patients and associated with immunoglobulin fractions.

Conclusions:

• MSAA is not indigenous to experimental animals and appears to infect humans.
• Strong evidence supports a close association between MSAA and MS.
• Not all MSAA infections may lead to the development of MS, suggesting a complex etiological pathway.