Specimen Nr. 04


Lymph node (Rat), immunologic reaction, secondary follicle


Alkaline-phosphatase technique, nucleus stained with hemalaun



Important structures :

1.Corona of a secondary lymphoid follicle
2.Germinal centre (dark zone) of a secondary follicle
3.Germinal centre (lightly-stained zone) of a secondary lymphoid follicle
Mit Antikörpern sind immunhistochemisch in blau B-Lymphozyten und in rot alle Zellen dargestellt, die sich in der S-Phase des Zellzyklus befinden. Die Korona enthält überwiegend B-Lymphozyten, die sich nicht teilen, während sich in der dunklen und hellen Zone des Keimzentrums viele B-Lymphozyten teilen. Proliferierende Lymphozyten werden auch im Paracortex und im Mark beobachtet.


Corona of a secondary lymphoid follicle
Germinal centre (dark zone) of a secondary follicle
Germinal centre (lightly-stained zone) of a secondary lymphoid follicle

Localisation of organs of immune-lymphatic system[we]

1. Pharyngeal tonsil
2. Palatine tonsil
3. Lymph node
4. Lymphatic vessels
5. Spleen
6. Peyer's patches
7. Thymus


Immunohistochemistry is used to confirm the presence of or to identify certain structures or substances in tissue sections which cannot be identified with conventional staining methods. Such structures include: cells, enzymes, hormones, macromolecules like nucleic acids and polysaccharides. The basis of immunohistochemical staining techniques is the antigen-antibody reaction. This method makes it possible to differentiate, for example, various cells in a tissue section according to their different metabolic products or surfaces. Either the metabolic product or a certain surface component serves as the antigen. In the first step, the antigen reacts with a specific antibody. The resulting antigen-antibody complex is invisible. Therefore, in a further step a second antibody bound to an adjuvant is added and binds to the initial antibody (so-called sandwich procedure). The bound adjuvant makes the antigen-antibody complex visible under the microscope and identifies the sought structure. Adjuvants are:

Combination with further dyes or staining techniques:

Wenn im Paracortex ein antigen-spezifischer T-Lymphozyt einen antigen-spezifischen B-Lymphozyten stimuliert, beginnt eine Immunantwort. Bei diesen Immunreaktionen nimmt die Durchblutung des Lymphknotens schnell zu, was zu einer schmerzhaften Anspannung der Lymphknotenkapsel führen kann. Außerdem induzieren die antigen-spezifischen B-Lymphozyten die Entwicklung von Sekundärfollikeln, in denen B-Lymphozyten entstehen, die nicht mehr niedrigaffines IgM, sondern hochaffines IgG, IgE oder IgA auf ihrer Oberfläche tragen. B-Lymphozyten, die ein Keimzentrum verlassen, entwickeln sich entweder zu Plasmazellen oder zu Gedächtniszellen.
Corona of a secondary lymphoid follicle
Germinal centre (dark zone) of a secondary follicle
Germinal centre (lightly-stained zone) of a secondary lymphoid follicle

HistoNet2000 - Help

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Right side: histologic specimen
Left side: information about the specimen (above) and general program functions (below)

2.Histologic specimen

Pull the mouse across the histologic specimen for training purposes. A small square with exclamation marks (dynamic labels) will appear where there is an important structure. You should then decide what structure this could be. To check your result, simply click the appropriate square, and the correct label will appear. The option “marked” allows you to see all labels for all structures simultaneously. These can be removed by clicking “unmarked”. This reactivates the dynamic labels.

3. Complementary information

Info: general information about the specimen, as well as a list of the dynamic labels
Drawing: schematic drawing of the specimen
Staining: information about the staining method for this specimen
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