Regulation of T-lymphocyte trafficking by ICAM-1, MAdCAM-1, and CCR7 in microcirculation of appendicular and intestinal lymphoid tissues.
OBJECTIVE
Although the appendix is recognized as an inductive site of intestinal inflammation, lymphocyte migration to lymphoid tissues of the appendix has not been characterized. The authors investigated if there are specific features in T-lymphocyte adhesion to microvessels of the appendix compared to mouse Peyer's patches (PPs).


METHODS
T-lymphocyte interaction with postcapillary venules (PCVs) of lymph follicles of the appendix and PPs was observed using an intravital microscope. Antibodies against ICAM-1, MAdCAM-1, or anti-L-selectin were administered prior to lymphocyte administration, and in some experiments CCR7 on T-lymphocytes was desensitized by excess CCL21.


RESULTS
The number of adhered T-lymphocytes reached the maximum value earlier in PCVs of PPs than in those of the appendix. T-lymphocyte adherence was significantly inhibited by anti-MAdCAM-1 at either the appendix or PPs, but adherence in the appendix was also significantly inhibited by anti-ICAM-1, suggesting a dependency on ICAM-1 in the appendix. Histologically, there was a significant ICAM-1 expression in the appendix. Desensitization of CCR7 suppressed T-cell adhesion in PCVs of the appendix and PPs to the same extent.


CONCLUSIONS
ICAM-1 appeared to be more important in T-lymphocyte sticking in PCVs of the appendix compared with intestinal PPs, while MAdCAM-1 and CCR7 were shown to play important roles in T-lymphocyte adherence in all sites.
Nagamatsu
Hideyasu
H
Second Department of Internal Medicine, National Defense Medical College, Saitama, Japan.
Tsuzuki
Yoshikazu
Y
Matsuzaki
Koji
K
Miyazaki
Junichi
J
Okada
Yoshikiyo
Y
Hokari
Ryota
R
Kawaguchi
Atsushi
A
Nagao
Shigeaki
S
Itoh
Kazuro
K
Miura
Soichiro
S
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001065:Appendix / Q000098:blood supply / Q000276:immunology*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000502:physiology*; D054421:Chemokine CCL21; D019742:Chemokines, CC / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte / Q000502:physiology*; D016023:Integrins / Q000032:analysis; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis / Q000502:physiology*; D007422:Intestines / Q000098:blood supply / Q000276:immunology*; D019041:L-Selectin / Q000032:analysis; D008221:Lymphoid Tissue / Q000098:blood supply / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008833:Microcirculation; D009088:Mucoproteins; D009928:Organ Specificity; D010581:Peyer's Patches / Q000098:blood supply / Q000276:immunology; D054400:Receptors, CCR7; D019707:Receptors, Chemokine / Q000032:analysis / Q000502:physiology*; D013601:T-Lymphocytes / Q000737:chemistry / Q000166:cytology*
D000911:Antibodies, Monoclonal; C515479:Ccl21c protein, mouse; C515371:Ccr7 protein, mouse; D015815:Cell Adhesion Molecules; D054421:Chemokine CCL21; D019742:Chemokines, CC; D016023:Integrins; C489082:Madcam1 protein, mouse; D009088:Mucoproteins; D054400:Receptors, CCR7; D019707:Receptors, Chemokine; D018799:Intercellular Adhesion Molecule-1; D019041:L-Selectin