Debating humoral immunity and epistemology: the rivalry of the immunochemists Jules Bordet and Paul Ehrlich

He reshaped the forefront of xenotransplantation: Agustin Pasqual Dalmasso (1933-2021)

Agustin Pasqual Dalmasso died in December 2021. He was 88 years old and an Honorary Member of the International Xenotransplantation Association. Gus made seminal contributions to understanding and overcoming the barrier complement system poses to xenotransplantation. Those endeavoring to advance xenotransplantation to clinical application and those seeking the most topics in which to devote their life's work could do no better than examining how Gus approached the subjects of his life's work.

Complementology's foundation: The 100-year anniversary of the Nobel Prize to Jules Bordet

The discovery of the complement system was associated with the creation of medical serodiagnosis in the early 20th century. Its biotechnological applications, usable even a century after its development by Jules Bordet, preceded for decades the proof of its biochemical rather than biophysical nature. Complement science has begun to emerge, thanks to the labs of Michael Heidelberger and his student Manfred Martin Mayer. Complementology had known difficult moments like the suicide of Louis Pillemer by swallowing the reagents of his laboratory following the criticisms of his discovery by Robert A. Nelson, Jr., in March 1957, at the Walter Reed Army Institute. This alternative complement pathway continues to revolutionize medicine by its implications as the principal component of immunosurveillance and as an amplification loop for plasma proteolytic cascades. Moreover, the drug designed in pathologies related to this pathway, eculizumab, was the most expensive drug in the world at the beginning of its marketing. Complementology promises great hopes in inflammatory and degenerative diseases, regenerative medicine, transplantation, and vector nanotechnology and as a diagnostic tool primarily in transplantation and inflammatory imaging. The moral and historical responsibility requires to make known this legacy to the new generation of doctors and scientists and also the technicians of the clinical laboratory of complementology throughout the world.

Secreted IgM: New tricks for an old molecule

Secreted IgM (sIgM) is a multifunctional evolutionary conserved antibody that is critical for the maintenance of tissue homeostasis as well as the development of fully protective humoral responses to pathogens. Constitutive secretion of self- and polyreactive natural IgM, produced mainly by B-1 cells, provides a circulating antibody that engages with autoantigens as well as invading pathogens, removing apoptotic and other cell debris and initiating strong immune responses. Pathogen-induced IgM production by B-1 and conventional B-2 cells strengthens this early, passive layer of IgM-mediated immune defense and regulates subsequent IgG production. The varied effects of secreted IgM on immune homeostasis and immune defense are facilitated through its binding to numerous different cell types via different receptors. Recent studies identified a novel function for pentameric IgM, namely as a transporter for the effector protein ″apoptosis-inhibitor of macrophages″ (AIM/CD5L). This review aims to provide a summary of the known functions and effects of sIgM on immune homeostasis and immune defense, and its interaction with its various receptors, and to highlight the many critical immune regulatory functions of this ancient and fascinating immunoglobulin.

Malaria's contribution to World War One - the unexpected adversary

Malaria in the First World War was an unexpected adversary. In 1914, the scientific community had access to new knowledge on transmission of malaria parasites and their control, but the military were unprepared, and underestimated the nature, magnitude and dispersion of this enemy. In summarizing available information for allied and axis military forces, this review contextualizes the challenge posed by malaria, because although data exist across historical, medical and military documents, descriptions are fragmented, often addressing context specific issues. Military malaria surveillance statistics have, therefore, been summarized for all theatres of the War, where available. These indicated that at least 1.5 million solders were infected, with case fatality ranging from 0.2 -5.0%. As more countries became engaged in the War, the problem grew in size, leading to major epidemics in Macedonia, Palestine, Mesopotamia and Italy. Trans-continental passages of parasites and human reservoirs of infection created ideal circumstances for parasite evolution. Details of these epidemics are reviewed, including major epidemics in England and Italy, which developed following home troop evacuations, and disruption of malaria control activities in Italy. Elsewhere, in sub-Saharan Africa many casualties resulted from high malaria exposure combined with minimal control efforts for soldiers considered semi-immune. Prevention activities eventually started but were initially poorly organized and dependent on local enthusiasm and initiative. Nets had to be designed for field use and were fundamental for personal protection. Multiple prevention approaches adopted in different settings and their relative utility are described. Clinical treatment primarily depended on quinine, although efficacy was poor as relapsing Plasmodium vivax and recrudescent Plasmodium falciparum infections were not distinguished and managed appropriately. Reasons for this are discussed and the clinical trial data summarized, as are controversies that arose from attempts at quinine prophylaxis (quininization). In essence, the First World War was a vast experiment in political, demographic, and medical practice which exposed large gaps in knowledge of tropical medicine and unfortunately, of malaria. Research efforts eventually commenced late in the War to address important clinical questions which established a platform for more effective strategies, but in 1918 this relentless foe had outwitted and weakened both allied and axis powers.

Birth of the science of immunology

The science of immunology emerged in the last of the 19th and the first of the 20th century. Substantial progress in physics, chemistry and microbiology was essential for its development. Indeed, microorganisms became one of the principal investigative tools of the major founders of that science - Louis Pasteur, Robert Koch, Ilya Ilich Metchnikoff, Paul Ehrlich and Jules Bordet. It is pertinent that these pioneering scientists were born when questioning and exploration were encouraged because of the legacies of the previous century of enlightenment. Mentors greatly aided their development. Their discoveries were shaped by their individual personalities. In turn they developed other contributors to the nascent field. Their discoveries included the types of leukocytes, the roles of neutrophils in inflammation and defence, cellular lysis due to complement, the principles of humoral and cellular immunology, passive and active immunization, tissue antigens, anaphylaxis, anaphylactoid reactions and autoimmunity. Their work formed the basis of modern immunology that developed many decades later. Immunology has enormously impacted our understanding of the pathogenesis, diagnosis and treatment of infections, immune-mediated disorders and inflammation. Burgeoning advances forecast further important clinical applications of immunology. Yet, their applications will be problematic because few physicians sufficiently understand the science. We propose that understanding modern immunology requires a grasp of how that science developed - who made the discoveries, how they were made, their successes and failures, their interactions and debates all reveal the foundation of modern immunology.

Jules Bordet (1870-1961): a bridge between early and modern immunology

Jules Bordet, a pioneering immunologist, lived until the dawn of molecular immunology. He was born in Belgium in 1870, obtained a medical degree in 1892, worked at l'Institut Pasteur in Paris from 1894 to 1901 and then established the Pasteur Institute of Brabant in Brussels. Before World War I, Bordet found that complement binds to antibody-antigen complexes regardless of the antigen or antibodies involved. Subsequently he developed the complement fixation test that was of diagnostic importance for several decades. For his research concerning complement he was awarded the 1919 Nobel Prize in Physiology or Medicine. During that period he also discovered anaphylatoxin, conglutinin, and the cause of whooping cough (Bordetella pertussis). After World War I he found how thrombin forms, how platelets participate in clotting, lysozyme in human milk and much of the biology of bacteriophages. In addition, Bordet worked fervently to limit weapons of mass destruction and promote peace until his death in 1961.

Ilya Ilich Metchnikoff (1845-1915) and Paul Ehrlich (1854-1915): the centennial of the 1908 Nobel Prize in Physiology or Medicine

Ilya Metchnikoff and Paul Ehrlich shared the 1908 Nobel Prize in Physiology or Medicine - Metchnikoff for discovering the major types and functions of phagocytes and Ehrlich for discovering the types of blood leukocytes, helping to uncover how to generate and use antibodies to protect against bacterial toxins, and formulating the receptor concept of antibodies binding to antigens. In 1908 phagocytic and humoral defences were thought to be unrelated but it was realized much later that they influence one other. Thus, it is fitting that the 1908 Nobel Laureates in Physiology or Medicine remain closely connected in the minds of modern immunologists. Metchnikoff and Ehrlich shared qualities of natural curiosity and tenacity coupled with remarkable inductive-mechanistic thinking and a zest for experimentation. However, their approaches to and methods of research were decidedly different - Metchnikoff's by evolutionary biology and an approach to experimentation via microscopy and Ehrlich's by an imaginative side-chain theory and organic chemistry.

The emergence of the drug receptor theory

Today, the concept of specific receptors for drugs and transmitters lies at the very heart of pharmacology. Less than one hundred years ago, this novel idea met with considerable resistance in the scientific community. To mark the 150th anniversary of the birth of John Newport Langley, one of the founders of the receptor concept, we highlight his most important observations, and those of Paul Ehrlich and Alfred Joseph Clark, who similarly helped to establish the receptor theory of drug action.

Moving beyond the immune self?

We are witnessing a significant challenge to immunology's basic tenet, the immune self. Such an 'entity' is increasingly regarded as polymorphous and ill defined as transplantation biology and autoimmunity have demonstrated phenomena that fail to allow faithful adherence to a strict dichotomy of self/nonself discrimination. Instead of searching for elusive criteria of 'self' and 'other', immune responses are increasingly studied as arising within complex contexts, which determine various degrees of reactivity or dormancy. When the character of the immune 'object' is determined by the context in which it appears, not its character as 'foreign' per se, self/nonself discrimination recedes as a governing principle. In such context-based models, 'ecologic' controls arise from the entire organism in which the immune system is fully integrated. In these systems, subject-object relationships become blurred. Viewed from this perspective, a new theoretical construction of the immune system, one originally proposed by Jerne, is contending with Burnet's theory of immune identity. Although it is too early to judge which theory will prove more capacious, it is already apparent that Jerne's formulation has had a decisive impact in shaping new models of immunity.