Anne Sundblad

Global Analysis of Antibody Repertoires. 1. An Immunoblot Method for the Quantitative Screening of a Large Number of Reactivities

This paper describes a procedure for analysing multiple antibody reactivities that explores a commercially available immunoblot system, and is based on a double staining of nitrocellulose membranes, revealing both antibody reactivities and the migration position of the blotted proteins in the membrane. Quantification of both stainings by densitometry allowed the accurate superposition of the immunoreactivity and total protein profiles of each Line. Moreover, the protein stainings ofthe different lanes could be adjusted with a simple‐scale transformation algorithm, correcting for possible distortions during electrophoretic migration, and allowing for the precise comparison ofthe immunoreactivity profiles in different lanes. The procedure is discriminatory enough to identify unique reactivity patterns in random pools of 104 activated B cells, and to define strain‐specific natural antibody repertoires. The utilily of this immunoblot method as an assay for simultaneously scoring multiple reactivities to hundreds of antigens in complex mixtures of antibodies, and thus defining antibody repertoires in a global manner, is discussed.

Stimulation of B and T cells by in vivo high dose immunoglobulin administration in normal mice

Adult BALB/c mice were injected intravenously with a preparation of pooled normal murine IgG (400 mg/kg/day, on five consecutive days) and studied 8, 15, and 60 days later. High dose IgG administration increased the total numbers of splenic activated B and CD4+ (but not CD8+) T cells, as well as the numbers of splenic Ig-secreting cells, particularly in the IgG isotypes. Reactivities to some autoantigens, but not to bacterial or other heteroantigens, were selectively amplified amongst IgM-secreting cells. IgG administration did not alter the specific primary immune response to heterologous erythrocytes or bacterial dextran. No cellular alterations were detected in the lymph nodes or peritoneal cavity of treated animals. Most of these effects subsided with time, but some autoantibody reactivities remained elevated 60 days later. The present results suggest that the therapeutic effects of high dose IgG administration which have been reported in human diseases might be associated with the immunostimulatory activities of such treatment.

Instability of Natural Antibody Repertoires in Systemic Lupus Erythematosus Patients, Revealed by Multiparametric Analysis of Serum Antibody Reactivities

Recent views on autoimmune diseases invoke generalized but specific perturbations in antibody repertoires, rather than the clonally restricted or non‐specific polyclonal alterations proposed thus far. The present experiments analyse serum antibody reactivities in 24 systemic lupus erythematosus (SLE) patients and 17 healthy controls, using a method that quantitatively scores a large number of antibody reactivities and allows for multiparametric statistical analyses. The results show global but relatively specific perturbations in SLE antibody repertoires, and identify novel disease‐associated reactivity patterns. Furthermore, a time series analysis of serum antibodies over 3 months demonstrates instability of natural antibody repertoires in individual SLE patients, contrasting with their remarkable conservation in healthy donors. Moreover, the method used clusters controls and patients independently, and might prove of diagnostic value, once large data bases are established.

Physiopathology of Autoimmunity: The Reactivities of Natural Antibodies Define the Boundaries of the Immunological Self

In modern Immunology, autoimmune diseases (AID) have a profound heuristic value that is not often considered. Every third year, in International Congresses such as this one, we are all exposed to the ever accelerating pace of progress in the analysis of components in the immune system (IS). All the more sobering, therefore, to contemplate AID and realise the extent of our current ignorance on the organization and operation of the IS. Thus, in contrast with other areas of modern medicine, we are today unable to recognise a diseased IS, before the target organ or tissue has been damaged. In other words, detection (and diagnosis ?) of AID is currently done on the basis of non-immunological parameters. Furthermore, we can of course not predict whether or not an IS will develop into an autoaggressive mode of operation, probably because, in this case, the diagnosis would have to be purely immunological. Finally, we know of no scientifically based procedure to correct immunodisfunction and bring a diseased IS back to the normal operation that characterises physiology. Thus, all established therapeutic strategies in use today aim at nonspecifically suppress all immune activities, with little consideration as to the detailed mechanism of disease, and none at all as to the specificities involved, and as to the origin of the process.