Lymph node: germinal center
After antigenic stimulation, those B cells that have been selected for their high affinity antibodies, undergo further proliferation forming large immunoblasts in the lighter zone of the germinal center. Immunoblasts divide to form plasma cells and B memory cells. Mitotic figures indicate this activity. Reticular connective tissue, produced by reticular cells, forms the stroma of the nodule. Macrophages and antigen-presenting cells are also present in the germinal center. 1000x
Germinal center >
The germinal center contains immunoblasts, cells with large, euchromatic nuclei and abundant cytoplasm. These cells divide, giving rise to plasma cells and B memory cells; mitotic figures reflect this activity. Antigen-presenting cells and macrophages with engulfed, phagocytosed particles are also present in the germinal center.
- Immunoblasts
The germinal center contains immunoblasts, cells with large, euchromatic nuclei and abundant cytoplasm. These cells divide, giving rise to plasma cells and B memory cells; mitotic figures reflect this activity. Antigen-presenting cells and macrophages with engulfed, phagocytosed particles are also present in the germinal center.
- Mitotic figures
The germinal center contains immunoblasts, cells with large, euchromatic nuclei and abundant cytoplasm. These cells divide, giving rise to plasma cells and B memory cells; mitotic figures reflect this activity. Antigen-presenting cells and macrophages with engulfed, phagocytosed particles are also present in the germinal center.
- Macrophages >
Macrophages (tingible body macrophages), with phagosomes in their cytoplasm, indicate the phagocytic activity occurring in the germinal center. The term “tingible” refers to the fact that the phagocytosed material is stainable.
Mantle
The germinal center contains immunoblasts, cells with large, euchromatic nuclei and abundant cytoplasm. These cells divide, giving rise to plasma cells and B memory cells; mitotic figures reflect this activity. Antigen-presenting cells and macrophages with engulfed, phagocytosed particles are also present in the germinal center.
Reticular cells >
The stroma of the entire lymph node is reticular connective tissue, an open meshwork of delicate reticular fibers on which are suspended the various cells functioning in the node and in this nodule. Reticular cells that produce this meshwork have nuclei that resemble those of active fibroblasts.
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