The possibility of using phytohaemagglutinin (PHA) in lectin immunotests was investigated. Antigens and antibodies were coupled to lectins of different origins using glutaraldehyde as the coupling reagent. The conjugates obtained wee used to quantitate human alpha-foetoprotein and anti-DNA or anti-actin antibodies in the serum of patients. The two PHA preparations used proved to be equally adequate for this type of immunoassay, and greater sensitivity was achieved with PHA than with ConA. PHA can now be added to the list of lectins available for quantitating antigens and antibodies by erythro-adsorption.

Actins↗

PubMedDate not supplied

Natural antibodies against tubulin, actin myoglobin, thyroglobulin, fetuin, albumin and transferrin are present in normal human sera, and monoclonal immunoglobulins from multiple myeloma and Waldenström's macroglobulinemia may express similar antibody specificities.

Sera from a pool of 800 healthy donors and from 3 individual healthy donors were passed through tubulin, actin, thyroglobulin, myoglobin, fetuin, transferrin and albumin immunoadsorbents. Proteins were eluted in all the immunosorbents and were found to be essentially composed of the three major Ig classes and albumin. The isolated Ig fractions were shown to react specifically, via their Fab fragment with the antigens and were specifically inhibited by them. These results strongly suggest that natural antibodies against the seven antigens are present in normal human serum, and probably against a high variety of self antigens. These results prompted us to search in the sera of patients with monoclonal gammapathies, paraproteins having natural antibody-like function. Among the 62 sera studied 3 were shown to react with actin and 1 with tubulin. Most important, these 4 monoclonal immunoglobulins exhibited similar specificities to that found with natural antibodies. This seems to indicate, that at least for some patients, the monoclonal immunoglobulins produced may represent the expansion of a clone producing a natural antibody.

Actins↗

PubMedDate not supplied

Regulation of the humoral immune response by polyspecific natural autoantibodies.

Two different BALB/c IgMk polyspecific monoclonal natural autoantibodies E7 and D23 were administered to neonatal BALB/c mice. When adults, these mice were immunized and challenged with calf myosin, BALB/c actin, human transferrin, calf thymus DNA or TNP-coupled bovine serum albumin (TNP/BSA), in complete Freund's adjuvant. The levels of serum antibody were evaluated by enzyme immunoassay. No differences in anti-actin, anti-transferrin and anti-DNA antibody titres were noted between control and antibody-treated mice. However, anti-myosin antibody titres significantly increased in mice treated with either the E7 or D23 antibody, and anti-TNP antibody titres significantly decreased in mice treated with E7 but not with D23. These differences persisted after antigenic challenge and involved only the IgG response of treated mice. These results suggest that polyspecific natural autoantibodies may be involved in the regulation of the humoral immune response.

Animals↗

PubMedDate not supplied

Comparative study of natural autoantibodies in the serum and cerebrospinal fluid of normal individuals and patients with multiple sclerosis and other neurological diseases.

Using a panel of antigens (actin, myosin, tubulin, albumin, transferrin, peroxidase, thyroglobulin, DNA, prolactin, TNP and myelin basic protein (MBP], we have tested the antibody activity of serum and cerebrospinal fluid (CSF) from healthy individuals, patients with multiple sclerosis (MS) and individuals with other neurological diseases. No differences in the concentrations and specificities of the serum antibodies were observed among the 3 groups. In contrast, we found that MS patients often had elevated CSF antibody levels against many antigens of the panel. The MS patients with local immunoglobulin production in the central nervous system (CNS) had the highest antibody levels. Restricted antibody activity against a given antigen of the panel was not observed. Compared to the two other groups, the MS group had equivalent titres of anti-MBP antibodies in the CSF. These results suggest that, in MS, a general immune dysregulation exists which leads to a local expansion of B lymphocytes producing autoantibodies with reactivities similar to those of serum natural autoantibodies.

Antibody Specificity↗

PubMedDate not supplied

Natural autoantibodies: the other side of the immune system.

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Animals↗