Toxicology

Tissue Cross Reactivity Studies

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Tissue Cross Reactivity Studies are key in the development of monoclonal antibodies and other related biologics. The purpose of the Tissue Cross Reactivity Study is to assure that the experimental antibody does not bind to epitopes other than the target site as this could lead to treatment-related toxicity in human subjects. 

Comparative Biosciences, Inc. Histology Laboratory provides complete and comprehensive Tissue Cross Reactivity Studies to support both research efforts and IND enabling studies for FDA submission. 

  • Complete tissue bank of human, primate, and other species-frozen and fixed tissues for human tissue cross reactivity studies as well as animal studies
  • Medical records and identification for human tissues
  • Study specific protocols prepared to reflect sponsor’s exact requirements
  • Strong expertise in immunohistochemistry, histology, and immunopathology with both animal and human tissues
  • Tissue evaluation by experienced ACVP board certified veterinary pathologist
  • Comprehensive, high-quality audited reports
  • Digital photomicroscopy upon request
  • Quality assurance with critical phase audits
  • Rapid scheduling and reporting
  • Reasonable cost-effective pricing

Phase 1: Initial Characterization and Optimization

For the initial characterization and optimization, the optimal specificity and staining conditions for the experimental antibody is determined.  Multiple dilutions (usually 5) and appropriate positive and negative control tissues are used to optimize and validate antibody dilution and relevant staining conditions. 

Phase 2: Preliminary Tissue Cross Reactivity Screening

Using the optimal specificity and staining conditions, a preliminary study with the standard 32 tissues is conducted and evaluated.

Adrenal Gland Gastrointestinal Tract Prostate
Bladder Heart Skeletal Muscle
Blood Cells Kidney Skin
Bone Marrow Liver Spinal Cord
Breast Lung Spleen
Cerebellum Lymph Node Testes
Cerebral Cortex Ovary Thymus
Colon Pancreas Thyroid
Endothelium Parathyroid Ureter
Eye Pituitary Uterus
Fallopian Tube Placenta  

Phase 3: Full Cross Reactivity Study

Following optimization in Phase 1 and 2, a full cross reactivity study can be performed in accordance with the FDA’s recommendation (“Points to Consider in the Manufacture and Testing of Monoclonal Antibody Products for Human Use”, FDA Guidance Document)

  • In this study, tissues are used from 3 unrelated adults
  • Experimental antibody at two dose levels
  • Isotype control antibody
  • β2 microglobulin on each tissue for staining control
  • Evaluation by ACVP board certified veterinary pathologist
  • Staining intensity scored 0-4
  • Conducted under GLP conditions with audits of critical phases
  • Final report suitable for FDA submission
  • Archiving

2+ staining in lymph node

4+ Staining in Skin

4+ Staining in tonsil

4+ staining in small artery

2+ staining in Lymph Node

4+ Staining in Skin

4+ Staining in Tonsil

4+ staining in Small Artery