Cellular Mechanisms of Antibacterial Defense in Lymph Nodes

Abstract

The origin of the polymorphonuclear leucocytes found in the intermediary and subcapsular sinuses of the popliteal lymph node during acute bacterial lymphadenitis, and the effect of this leucocyte infiltration on the passage of bacteria through the lymph node have been investigated. It has been demonstrated that: 1. The polymorphonuclear leucocytes in the nodal sinuses originate both from blood vessels of the lymph node and from the primary inflammatory focus in the tissues. 2. Granulocytes invading the intermediary sinuses of the infected lymph node arise primarily from capillaries lining these sinuses. 3. Most of the polymorphonuclear leucocytes in the subcapsular sinus, on the other hand, originate from the inflammatory focus in the tissues and appear to traverse the node by way of this peripheral sinus. 4. The bacteremia following direct intralymphatic injection of pneumococci is suppressed by the presence of preformed inflammatory exudate in the nodal sinuses indicating that the filtering capacity of the node is thereby greatly increased.

Pulmonary Edema in Influenzal Pneumonia of the Mouse and the Relation of Fluid in the Lung to the Inception of Pneumococcal Pneumonia

“…this capacity. A similar slow action of macrophages has been found in experimental pneumococcal lymphadenitis of rats (45). However, in this situation, migration of polymorphonuclear leucocytes is more rapid than in the normal mouse lung and suggests some difference in capillary permeability in these two sites.…”

Bacterial Lymphatic Metastasis in Infection and Immunity

“…Although lymph nodes are best known for their role in sampling antigens from tissues and coordinating durable adaptive immune responses [ 160 , 161 ], their contribution to innate defence against bacteria through the actions of resident and recruited phagocytes was first identified in the late 19th century [ 6 , 162 , 163 ]. As such, bacteria surviving within the lymph node must possess suitable virulence factors to resist phagocytic killing through either avoidance of phagocytosis or survival upon phagocytosis [ 164 ].…”

“…In shorter time course experiments, bacterial passage through the lymph node has been reported to be greatest in the initial minutes or hours following injection [ 163 , 171 ]. These factors indicate that an early rush of bacteria may be able to disseminate through the lymph node with great efficiency before cellular defences respond.…”

“…Increased filtration efficiency over time coincides with the inflammatory response in the lymph node [ 163 ]. As with bacterial infections at other sites in the body, neutrophils are first responders in the lymph node and seem to be key players in the bactericidal response.…”

“…Following intradermal injection of pneumococci, roughly 50% of cells in the afferent lymphatic of the local draining lymph node are neutrophils [ 163 ]. Neutrophils have also been observed in these vessels after infection with other bacteria, including S. aureus and M. bovis [ 17 , 174 ].…”