Distinct roles for LTalpha3 and LTalpha1beta2 produced by B cells contribute to their multi-faceted impact on ileitis.

B lymphocytes may facilitate chronic inflammation through antibody production or secretion of cytokines, including lymphotoxin (LT)-ab associated with development of lymphoid tissue. Tertiary lymphoid structures (TLS) characterize human and murine ileitis by suppressing outflow from the ileum. Here, we show that B cell-derived secretory IgA protected against ileal inflammation, whereas B cell-derived LTa guarded against ileitis-associated loss of body mass.

Halogen-bonded zigzag mol-ecular network based upon 1,2-di-iodo-perchloro-benzene and the photoproduct -1,3-bis-(pyridin-4-yl)-2,4-di-phenyl-cyclo-butane.

The formation and crystal structure of a zigzag mol-ecular network held together by I⋯N halogen bonds is reported. In particular, the halogen-bond donor is 1,2-di-iodo-perchloro-benzene ( ) while the acceptor is a head-to-tail photoproduct, namely -1,3-bis-(pyridin-4-yl)-2,4-di-phenyl-cyclo-butane ( ). In this co-crystal ( )·( ), the donor acts as a bent two-connected node while the acceptor behaves as a linear linker to form the extended solid.

Controlling Topology within Halogen-Bonded Networks by Varying the Regiochemistry of the Cyclobutane-Based Nodes.

The formation of a pair of extended networks sustained by halogen bonds based upon two regioisomers of a photoproduct, namely -1,3-bis(4-pyridyl)-2,4-bis(phenyl)cyclobutane (-PP) and -1,2-bis(4-pyridyl)-3,4-bis(phenyl)cyclobutane (-PP), that have varied topology is reported. These networks are held together via I⋯N halogen bonds between the photoproduct and the halogen-bond donor 1,4-diiodoperchlorobenzene (CICl). The observed topology in each solid is controlled by the regiochemical position of the halogen-bond accepting 4-pyridyl group.