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Genetically determined CD45 variant of value in leucocyte tracing in vivo in the pig
R M Binns1, S T Licence, A Whyte
1Department of Immunology, Babraham Institute, Cambridge, UK.
Abstract:
This paper describes a monoclonal antibody (mAb), anti-pig CD45 (MAC323), that is directed against a polymorphic determinant. A monomorphic anti-pig CD45 mAb (K252.1E4) bound strongly to leucocytes from both MAC323+ and MAC323- pigs, demonstrating the absence of the epitope rather than the CD45 molecule. The MAC323 determinant was present on all leucocytes in positive pigs, exhibiting different expression levels on subsets (monocytes > lymphocytes > polymorphs), but was absent on red blood cells. Pigs lacking this determinant were healthy and grew normally. Careful selection of male and female SLAb/b pigs produced families that were either positive or negative for this epitope. Interbreeding within these families identified the genetic segregation of this variation, which is consistent with the CD45(323) epitope being inherited as a simple dominant autosomal gene. The lack of this determinant in certain lines of inbred pigs has been used to study the homing, lifespan and tissue distribution of donor unlabelled MAC323+ leucocytes and their subsets (using single- and two-colour immunocytological techniques) in MAC323- recipients after either intravenous injection or exchange transfusion. These results, identifying trafficking areas and subsets in constitutive lymphoid and inflammatory tissues, obtained using this genetic marker, extend those obtained previously using fluorescein isothiocyanate (FITC)-labelled donor cells.
Insights
Researchers developed a new monoclonal antibody (mAb), MAC323, to study pig CD45. This genetic marker helps track leukocyte movement and lifespan in pigs, advancing immunology research.
Area of Science:
- Immunology
- Genetics
Background:
- CD45 is a crucial protein on leukocytes.
- A novel polymorphic determinant on pig CD45 was identified.
Purpose of the Study:
- To characterize the anti-pig CD45 monoclonal antibody (mAb), MAC323.
- To investigate the genetic inheritance of the MAC323 epitope.
- To utilize this genetic marker for leukocyte tracking studies.
Main Methods:
- Monoclonal antibody production and characterization (MAC323).
- Immunocytological techniques (single- and two-colour) for analyzing leukocyte subsets.
- Genetic analysis of epitope segregation in pig families.
- Leukocyte homing, lifespan, and tissue distribution studies in vivo.
Main Results:
- The MAC323 mAb recognizes a polymorphic determinant on pig CD45, not the entire molecule.
- The CD45(323) epitope is inherited as a simple dominant autosomal gene.
- Pigs lacking the epitope are healthy and grow normally.
- MAC323-negative pigs serve as recipients for tracking unlabeled MAC323-positive leukocytes, revealing trafficking patterns.
Conclusions:
- The MAC323 epitope is a valuable genetic marker for studying leukocyte dynamics in pigs.
- This genetic marker facilitates detailed analysis of leukocyte homing, lifespan, and tissue distribution.
- The findings enhance our understanding of constitutive lymphoid and inflammatory tissue interactions.