The demonstration of locally synthesized herpes simplex IgG antibodies in CSF by a Sepharose 4B linked enzyme immunoassay.

A newly developed peroxidase-linked immunoassay is described which is sensitive enough to quantify herpes simplex antibodies in serum and cerebrospinal fluid diluted to an IgG level of 1 mg/dl. Thus, a comparison of photometric signals allows the direct detection of specific antibodies which have been secreted by activated tissue B lymphocytes into the CSF compartment during the humoral immune phase of herpes simplex encephalitis. The technique utilizes urea-Triton-dissolved virus antigens covalently bound to Sepharose 4B pearls. A highly specific sandwich antibody was purified by immune absorption column chromatography and labelled in its protected state. In the majority of cases the antibody level increased around the 10th day, to reach its maximum a few days after. In some cases however the serum levels gradually rose over a period of several weeks. The antibody levels in the CSF increase uniformly at the same time, irrespective of the general immune response and soared up to higher than serum levels within a few days. Local antibody production may persist for years so that late diagnosis of herpes encephalitis becomes possible with a single side by side test of serum and CSF from the patient.