Three methods for producing fertile hemopoietic chimeras in mice

Area of Science:

• Immunology
• Developmental Biology
• Reproductive Biology

Background:

• Semiallogeneic chimeras are valuable models for studying immune tolerance and development.
• Previous methods for generating these chimeras often resulted in compromised fertility.
• Retaining or regaining fertility in chimeric models is crucial for long-term studies.

Purpose of the Study:

• To describe and compare three distinct methods for producing semiallogeneic hemopoietic chimeras.
• To evaluate the efficiency of hemopoietic chimerism and fertility across these methods.
• To identify optimal strategies for generating fertile chimeric mice.

Main Methods:

• Prenatal (PN) chimera production involved injecting F1 fetal liver or adult bone marrow cells into early gestation embryos.
• Neonatal (NN) chimera production utilized intravenous injection of F1 bone marrow cells into newborn female mice.
• Ovary-transplanted (OT) chimeras were generated by irradiating adult females, repopulating with F1 bone marrow, and subsequently transplanting syngeneic ovaries.

Main Results:

• Hemopoietic chimerism levels were highest in the PN group (mean 27.1%), intermediate in the OT group (mean 18.1%), and lowest in the NN group (mean <14%).
• Fertility was notably best observed in BALB/c host PN chimeras.
• Donor H-2 phenotype marker expression on splenic lymphocytes was used to quantify hemopoietic chimerism.

Conclusions:

• Prenatal method is the most effective for establishing high-grade hemopoietic chimerism and preserving fertility in semiallogeneic models.
• Neonatal method resulted in significantly lower chimerism levels.
• Ovary transplantation offers an alternative but less efficient approach for generating fertile chimeras.