Immunodeficiencies & Monoclonal Antibody Technology

dr. thomas 641

Immunodeficiencies: Innate Immune System

Immunodeficiencies: Adaptive Immune

System

Congenital Immunodeficiencies: Lymphocyte

Maturation

Congenital Immunodeficiencies: Defects in Lymphocyte Maturation

Congenital Immunodeficiency Due to Defects in Lymphocyte Function

• Note the two types of the genetic deficiencies that cause lymphocyte function deficiency

  • Exam question

    • one one type of antibody made - Hyper IgM state

      • if only making the IgM antibody, this immune system is defective, really want IgG antibodies

• AID - activation induced deaminase

• Th1 cell + CD40L - activates macrophages and signals to the B cell, which activates AID

  • understand what AIDs function is

  • understand CD40L mutation, this is more severe

Acquired (Secondary) Immunodeficiencies

HIV infection causes immunodeficiency by attacking host immune cells

• when host is first exposed, virus dragged to lymph notes, experience a viremia

• virus, being a retro-virus, starts to rotate and mutates, making it harder to eradicate - sits in lymph nodes and avoids immune detection

• helper CD4+ cells not there/lost is thought to not recruit specific CTLs?

Anti-Viral Treatment Targets Strategic Points of Viral Life Cycle

Note where these agents target in the viral life cycle - these attempt to control the replication of the virus … by turning on CTLs when CD4+ helper cells are lost

• reverse transcriptase inhibitors

• integrase inhibitors

• protease inhibitors

Antibody repertoire produced by recombination in developing B cell

Monoclonal antibody production via hybridoma

• take a mouse and bias its immune system with a chemical structure injection, isolate B cell from the mouse, immortalize the B cell by fusing it with a cancer cell - have an infinite source of B cells and store them away until needed

  • generate B cell population - recall its function/significance

  • then screen the mice for the one with the best characteristics that reacts to the antigen, which in this case is a drug molecule

• Labor Intensive

  • Slow- inefficient (fusion % low)

  • Antigen Limitations (Must be immunogenic/nontoxic)

• Antibodies from Mice may induce Hypersensitivity Reactions (e.g., Type III Immune Complex Rx)

• Need to “humanize” Antibody or use Transgenic Mouse with “Human” Immune system

Limitations

• If you want to generate an antibody to the antigen/target, know the constraints of the antigen:

  • the antigen has to stimulate an immune response

  • antigen cannot be toxic, has to surpass minimal constraints

Companion Technologies for Monoclonal Antibody Production

• Generation of a “Naïve” Human Antibody Library

• Employs Phage Display method for screening Antibody binding

• Clone Antibody Genes in Expression System, e.g., CHO cells

• isolate B cells

  • presents population

• understand how this first step leads to critical gene? modifications

Biosimilars