Why current quantitative serology is not quantitative and how systems immunology could provide solutions

Orosz

et al. 2022

Sensors

Self Cite

In spite of its pivotal role in the characterization of humoral immunity, there is no accepted method for the absolute quantitation of antigen-specific serum antibodies. We devised a novel method to quantify polyclonal antibody reactivity, which exploits protein microspot assays and employs a novel analytical approach. Microarrays with a density series of disease-specific antigens were treated with different serum dilutions and developed for IgG and IgA binding. By fitting the binding data of both dilution series to a product of two generalized logistic functions, we obtained estimates of antibody reactivity of two immunoglobulin classes simultaneously. These estimates are the antigen concentrations required for reaching the inflection point of thermodynamic activity coefficient of antibodies and the limiting activity coefficient of antigen. By providing universal chemical units, this approach may improve the standardization of serological testing, the quality control of antibodies and the quantitative mapping of the antibody–antigen interaction space.

Section: Discussionmentioning

confidence: 99%

Absolute Quantitation of Serum Antibody Reactivity Using the Richards Growth Model for Antigen Microspot Titration

Papp¹,

Orosz

et al. 2022

Sensors

Self Cite

“…The introduction of such quantitative assays could not only improve diagnostic accuracy of immunoassays but would also pave the way to our quantitative understanding of the adaptive immune system. The generalized quantitative model of antibody homeostasis [3] provides a conceptual framework for the experimental mapping of the "antibodyome" [48][49][50], a goal that could be achieved by the strategic mapping of antigen structural space. The integration of quantitative binding information into a network and the mapping of the interaction network [49] to the sequence space generated by next generation sequencing [51] is expected to bring about unprecedented systemic understanding of adaptive immunity in particular and protein evolution in general.…”

Section: Discussionmentioning

confidence: 99%

Absolute quantitation of serum antibody reactivity using the Richards growth model for antigen microspot titration

Papp¹,

Orosz

et al. 2021

Preprint

Self Cite

In spite of its pivotal role in the characterization of humoral immunity, there is no accepted method for the absolute quantitation of antigen specific serum antibodies.We devised a novel method to quantify polyclonal antibody reactivity, which exploits protein microspot assays and employs a novel analytical approach. Microarrays with a density series of disease specific antigen were treated with different serum dilutions and developed for IgG and IgA binding. By fitting binding data of both dilution series to a product of two generalized logistic functions, we obtained estimates of antibody reactivity of two immunoglobulin classes simultaneously. These estimates are the antigen concentrations required for reaching the inflection point of thermodynamic activity coefficient of antibodies and the limiting activity coefficient of antigen.By providing universal chemical units, this method may improve standardization of serological testing, the quality control of antibodies and the quantitative mapping of antibody-antigen interaction space.

“…The units obtained this way do not allow any kind of comparison of results, even for the identical antigen when different platforms are used, or different antibody isotypes are measured. The units are standardized but arbitrary with no biochemical meaning [ 35 ].…”

Section: Probing Serum Antibody Configuration Space: Quantitative Sys...mentioning

confidence: 99%

The Binding Landscape of Serum Antibodies: How Physical and Mathematical Concepts Can Advance Systems Immunology

Prechl¹,

Papp²,

et al. 2022

Antibodies

Self Cite

Antibodies constitute a major component of serum on protein mass basis. We also know that the structural diversity of these antibodies exceeds that of all other proteins in the body and they react with an immense number of molecular targets. What we still cannot quantitatively describe is how antibody abundance is related to affinity, specificity, and cross reactivity. This ignorance has important practical consequences: we also do not have proper biochemical units for characterizing polyclonal serum antibody binding. The solution requires both a theoretical foundation, a physical model of the system, and technology for the experimental confirmation of theory. Here we argue that the quantitative characterization of interactions between serum antibodies and their targets requires systems-level physical chemistry approach and generates results that should help create maps of antibody binding landscape.