Immunology's first priority dispute--an account of the 17th-century Rudbeck-Bartholin feud

Modern immunology has been notably free of public disputes over credit for major discoveries in this discipline. But the early recognition of the lymphatic system witnessed two examples of heated priority feuds. The first in the 17th-century concerned the greater anatomical organization of the system, while the second in the 18th-century concerned its function. This essay reviews the earlier of the two disputes, in which a Swedish medical student (Ole Rudbeck) charged a respected Danish Professor (T. Bartholin) with plagiarism and antedating his observations. Thus ethical issues in immunology predate modern times. How this discipline reached this point in its history is another focus of this essay and also an excuse to review briefly the anatomy of the lymphatic system. The influence of nationalistic pride on priority disputes is also discussed.     

The complexus adhaerens of mammalian lymphatic endothelia revisited: a junction even more complex than hitherto thought

The significance of a special kind of VE-cadherin-based, desmoplakin- and plakoglobin-containing adhering junction, originally identified in certain endothelial cells of the mammalian lymphatic system (notably the retothelial cells of the lymph node sinus and a subtype of lining endothelial cells of peripheral lymphatic vessels), has been widely confirmed and its importance in the formation of blood and lymph vessels has been demonstrated in vivo and in vitro. We have recently extended the molecular and structural characterization of the complexus adhaerens and can now report that it represents a rare and special combination of components known from three other major types of cell junction. It comprises zonula adhaerens proteins (VE-cadherin, α- and β-catenin, protein p120^ctn, and afadin), desmosomal plaque components (desmoplakin and plakoglobin), and tight-junction proteins (claudin-5 and ZO-1) and forms junctions that vary markedly in size and shape. The special character and the possible biological roles of the complexus adhaerens and its unique ensemble of molecules in angiogenesis, immunology, and oncology are discussed. The surprising finding of claudin-5 and protein ZO-1 in substructures of retothelial cell-cell bridges, i.e. structures that do not separate different tissues or cell layer compartments, suggests that such tight-junction molecules are involved in functions other than the “fence” and “barrier” roles of zonulae occludentes. This work was supported by a grant from the Deutsche Forschungsgemeinschaft (DFG grant MO 345/5-2). This study is part of a thesis presented to the Faculty of Medicine of the University of Heidelberg, Germany, to fulfil the requirements of the doctoral degree (MD) of the first author.     

Duplication mutation in CHIT1 gene is associated with poor response to medical therapy in patients affected with filarial chyluria

We explore the impact of CHIT1 gene mutation on clinical, biochemical parameters and response to outcome (remission/failure) of medical treatment in North Indian filarial chyluria (FC) patients. Data of 101 subjects of FC treated medically between March 2013 and April 2016 in whom CHIT1 gene polymorphism was determined were analyzed. Filarial etiology was confirmed by DEC-provocative test, immuno-chromatographic test and IgG/IgM-combo rapid antibody test. CHIT1 gene polymorphism was genotyped by polymerase chain reaction. Of 101 patients (mean age, 36.9±10.28 years; male: female, 3:1.2), 66 experienced remission (Group-A) while 35 experienced relapse or failed to respond (Group-B). A significant association was observed between CHIT1 genotypes and higher grade of disease (p= 0.001). Wild-type, heterozygous and homozygous mutant frequencies of CHIT1 genotypes were 78.6%, 72.5% and 27.8% in remission and 21.4%, 27.5% and 72.2%, in recurrence/failure, respectively. Our results showed that patients with mutant genotype (TT) of CHIT1 gene showed significantly higher rate of recurrence or failure to medical therapy than wild type (HH) genotypes [OR (95% CI) = 9.53 (1.84-49.21), p=0.011]. This preliminary study showed the impact of CHIT1 gene variants on treatment outcome in FC patients. This observation needs to be confirmed using studies with larger numbers of FC patients.     

Genome wide computational analysis of Brugia malayi helicases: a comparison with human host

The availability of Brugia malayi genome sequence has paved ways for the search of homologues for a variety of genes. Helicases are ubiquitous enzymes involved in all the nucleic acid metabolic pathways and are essential for the development and growth. The genome wide analysis of B. malayi for different helicases showed the presence of a number of DEAD box helicases, 7 DEAH box helicases, RecQ helicases, repair helicases, super killer helicases, MCM2-7 complex, Rad54 and two subunits of Ku helicase. The comparison of protein sequence of each helicase with its human counterpart indicated characteristic differences in filarial helicases. There are noticeable differences in some of the filarial helicases such as DHX35, RecQL1 and Ku. Further characterization of these helicases will help in understanding physiological significance of these helicases in filarial parasites, which in future can be utilized for chemotherapy of parasitic infection.     

Defective remodeling and maturation of the lymphatic vasculature in Angiopoietin-2 deficient mice

Molecular mechanisms regulating the remodeling of the lymphatic vasculature from an immature plexus of vessels to a hierarchal network of initial and collecting lymphatics are not well understood. One gene thought to be important for this process is Angiopoietin-2 (Ang-2). Ang2^−/− mice have previously been reported to exhibit an abnormal lymphatic phenotype but the precise nature of the lymphatic defects and the underlying mechanisms have yet to be defined. Here we demonstrate by whole-mount immunofluorescence staining of ear skin and mesentery that lymphatic vessels in Ang2^−/− mice fail to mature and do not exhibit a collecting vessel phenotype. Furthermore, dermal lymphatic vessels in Ang2^−/− pups prematurely recruit smooth muscle cells and do not undergo proper postnatal remodeling. In contrast, Ang2 knock-out Ang1 knock-in mice do develop a hierarchal lymphatic vasculature, suggesting that activation of Tie-2 is required for normal lymphatic development. Taken together, this work pinpoints a specific lymphatic defect of Ang2^−/− mice and further defines the sequential steps in lymphatic vessel remodeling.     

Cranial nerves in the Australian lungfish,Neoceratodus forsteri,and in fossil relatives (Osteichthyes: Dipnoi)

Three systems, two sensory and one protective, are present in the skin of the living Australian lungfish, Neoceratodus forsteri, and in fossil lungfish, and the arrangement and innervation of the sense organs is peculiar to lungfish. Peripheral branches of nerves that innervate the sense organs are slender and unprotected, and form before any skeletal structures appear. When the olfactory capsule develops, it traps some of the anterior branches of cranial nerve V, which emerged from the chondrocranium from the lateral sphenotic foramen. Cranial nerve I innervates the olfactory organ enclosed within the olfactory capsule and cranial nerve II innervates the eye. Cranial nerve V innervates the sense organs of the snout and upper lip, and, in conjunction with nerve IX and X, the sense organs of the posterior and lateral head. Cranial nerve VII is primarily a motor nerve, and a single branch innervates sense organs in the mandible. There are no connections between nerves V and VII, although both emerge from the brain close to each other. The third associated system consists of lymphatic vessels covered by an extracellular matrix of collagen, mineralised as tubules in fossils. Innervation of the sensory organs is separate from the lymphatic system and from the tubule system of fossil lungfish.     

Modulation of lymphatic distribution of subcutaneously injected poloxamer 407-coated nanospheres: the effect of the ethylene oxide chain configuration

Lymphatic distribution of interstitially injected poloxamer 407-coated nanospheres (45 nm in diameter) is controlled by surface configuration of the ethylene oxide (EO) segments of the adsorbed copolymer. At low poloxamer surface coverage, EO tails spread laterally on a nanosphere surface and assume a ‘flat or mushroom-like’ configuration. Such entities drain rapidly from the subcutaneous site of injection into the initial lymphatic, when compared to uncoated nanospheres, and subsequently are captured by scavengers of the regional lymph nodes. In vitro experiments have also confirmed that such entities are prone to phagocytosis. When the equilibrium poloxamer concentration is at 75 μg/ml or greater the EO chains become more closely packed and project outward from the nanosphere surface. These surface-engineered nanospheres drain faster than those with EO chains in mushroom configurations into the initial lymphatic, escape clearance by lymph node macrophages, reach the systemic circulation, and remain in the blood for prolonged periods. These experiments provide a rational approach for the design and engineering of nano-vehicles for optimal lymphatic targeting and are discussed.     

Lymphatic filariasis: new insights into an old disease

Lymphatic filariasis has afflicted people in the tropical areas of the world for thousands of years but even up to comparatively recent times it has been poorly understood and its importance under recognised. In the last 2 decades or so there has been a flurry of activity in filariasis research, which has provided new insights into the global problem of filariasis, the pathogenesis of filarial disease, diagnosis and control.