Polyspecific Response Research Articles

Sensory Neuropeptides Prime the Splenic Marginal Zone for Optimal Humoral Immunity

Effective spleen-derived humoral responses are essential for protecting hosts from blood-borne pathogens. Increased susceptibility to infection is therefore a risk post-splenectomy but is also associated with smoking, chemotherapy and aging. In fact, decreased vaccine efficacy in the elderly may be due to splenic hypofunction. While investigating the role of sensory nerves in hematopoiesis, we discovered a lymphocytosis phenotype involving the splenic marginal zone (MZ). Dividing red and white pulp in the spleen, the MZ is a specialized micro-anatomic structure facilitating innate and adaptive crosstalk to incoming antigen. Sensory nerves were found to synapse at this site and in mice deficient in the major sensory neurotransmitter substance P (Tac-1-/-), MZs were expanded histologically and confirmed by flow cytometry as an increase involving the IgMhiIgDloCD21hiCD23lo MZ B cell population. Tac-1-/- mice also exhibited splenomegaly with overall Ki-67 proliferation indices of 40% vs. 5% in controls. In the peripheral blood, Tac-1-/- mice had persistent polyclonal pan-B cell lymphocytosis with an absolute increase of 200% relative to wildtype. Aberrant B cell homeostasis had functional consequences as demonstrated by significantly decreased total basal plasma IgG (P<0.001) but not IgM, suggesting a transitional defect from the low-affinity T-independent (TI) polyspecific response to T-dependent (TD) mature germinal center derived antibodies. Mechanistically, MZ B cell migration to follicles is required for optimal TD responses where they shuttle antigen-laden IgM immune complexes. Since MZ B cell activation can occur independently of the B cell receptor, relying on Toll-like receptors or other pattern recognition receptor ligation – it is reasonable to include neuropeptide release as an additional stimulus coordinating appropriate MZ B cell mobilization. A working hypothesis therefore is inflammatory stimuli conveyed by the sensory nervous system, which may or may not involve perceptible pain sensation, is rapidly conveyed to the splenic MZ via release of substance P. This may provide an integrated communication network facilitating optimal antibody formation, more efficient than relying on diffusion of conventional danger signals or chemokines alone. TI and TD antigen challenge, cell tracing and electrode stimulation experiments are underway to confirm this theory. Splenic sensory nerve manipulation or pharmacological modulation of the substance P axis may have therapeutic applications for boosting humoral immunity in a variety of immune compromised states. DisclosuresNo relevant conflicts of interest to declare.

Paradoxical suppression of poly-specific broadly neutralizing antibodies in the presence of strain-specific neutralizing antibodies following HIV infection

One of the first immunologic responses against HIV infection is the presence of neutralizing antibodies that seem able to inactivate several HIV strains. Moreover, in vitro studies have shown the existence of monoclonal antibodies that exhibit broad crossclade neutralizing potential. Yet their number is low and slow to develop in vivo. In this paper, we investigate the potential benefits of inducing poly-specific neutralizing antibodies in vivo throughout immunization. We develop a mathematical model that considers the activation of families of B lymphocytes producing poly-specific and strain-specific antibodies and use it to demonstrate that, even if such families are successful in producing neutralizing antibodies, the competition between them may limit the poly-specific response allowing the virus to escape. We modify this model to account for viral evolution under the pressure of antibody responses in natural HIV infection. The model can reproduce viral escape under certain conditions of B lymphocyte competition. Using these models we provide explanations for the observed antibody failure in controlling natural infection and predict quantitative measures that need to be satisfied for long-term control of HIV infection.

Induction of multiple CD8+ T cell responses against the inducible Hsp70 employing an Hsp70 oligoepitope peptide

The inducible heat shock protein Hsp70 has been described as a tumour antigen being frequently overexpressed in tumours of various histologic origins, with a role in tumourigenicity, as a critical event in tumour progression. A strategy to enhance the immune response to an antigen is the identification of multiple epitopes and the induction of a polyspecific response. Applied to tumour vaccination, such a polyspecific response should lead to a more robust antitumour efficacy. The long peptide Hsp70380-402 encompasses three nonamer peptides with a high affinity for HLA-A *0201. In a previous paper, we have shown that two of these nonamer peptides, p391 and p393, can raise CTL to recognize tumour cells overexpressing Hsp70. In the present paper, we demonstrate that the third nonamer peptide, p380, is a new epitope efficient in raising an antitumour immune response. The p380-402 polypeptide was able to induce an immune response against each of the three constituent epitopes both in vivo in HLA-A *0201 transgenic mice and in vitro with human PBMC. This polypeptide therefore constitutes an interesting candidate for the induction of multiple HLA-A *0201-restricted anti-Hsp70 antitumour CTL responses.

Gangliosides, Ab1 and Ab2 antibodies: III. The idiotype of anti-ganglioside mAb P3 is immunogenic in a T cell-dependent manner

P3 mAb is an IgM monoclonal antibody specific for N-glycolyl-containing gangliosides. The immunogenicity of the P3 idiotype has been previously described by immunizing syngeneic BALB/c mice with the purified murine IgM or the mouse-human chimeric IgG antibody. In the present work we study the antibody response against the idiotype of P3 mAb through immunization with DNA. We used small immune proteins (SIP) consisting on the idiotype in the scFv format, covalently linked to γ1CH3, the self-dimerizing domain of murine IgG1. SIPs were previously shown to be appropriate to induce specific anti-idiotypic responses. By gene gun immunization, a polyspecific response was occasionally generated, particularly with the P3 idiotype. A single shot of DNA was sufficient to induce a strong and long-lasting anti-P3 idiotype response. In addition, by delivery of the same DNA construct with a recombinant adeno-associated virus the unique immunogenicity of the P3 idiotype was demonstrated. The requirement of T cells in the anti-P3 idiotype response was indicated by the lack of P3-specific anti-idiotypic antibodies following immunization of both, allogeneic C57BL/6 and athymic BALB/c mice.

Respuesta inmune poliespecífica en el sistema nervioso central. Empleo del índice de anticuerpo

The immune response, oligoclonal in cerebrospinal fluid (CSF), in comparison with the blood evidences is different and polyspecific. Together with specific antibodies against the causative agent, antibodies with many different specificities were synthesized. It is more complex in chronic neurological diseases. Broadcast the characteristics of the polyspecific oligoclonal response and the use of antibody index as diagnostic tool in infectious and chronic diseases. The use of antibody index discriminates between the blood-derived antibody fraction and the brain-derived specific antibody fraction. Once the CSF/serum specific antibody and the IgG ratio are calculated, the antibody index is the quotient between both ratios. Antibody specific ratio may be obtained by titulation but it is less sensible. It is much better to employ immunoenzymatic methods. To avoid false negative results we must use the limit ratio according to reibergram instead of IgG ratio when the last one is greater than the limit ratio. Pathological antibody indexes are > or = 1.5. In chronic, autoimmune diseases, like lupus eritematosus, Sjögren syndrome or Wegener granulomatosis, could exist pathological antibody index against different viral agents like the antibody index against measles (M), rubella (R) and zoster (Z) viruses, known as MRZ reaction. The use of antibody index permits the diagnosis of infectious neurological diseases and the characterization of the secondary polyspecific response in chronic neurological processes.

Neuroimmunoregulation and natural immunity

The development and function of the immune system is regulated by neuroendocrine factors. Immune function may be divided into adaptive and natural immunity. Adaptive immune responses are driven by specific determinants of the antigen (epitopes), require 5–10 d to fully develop, and show an accelerated or memory response after repeated exposure to the same antigen. Natural immunity may be divided into host defense mediated by non-immune factors (e.g., antimicrobial proteins, enzymes, mucus etc.) and polyspecific responses of the immune system. This polyspecific response relies on natural antibodies and on some other serum proteins (e.g., lipopolysaccharide-binding protein-LBP, C-reactive protein-CRP), and on surface receptors of macrophages, natural killer cells and B and T lymphocytes for activation. Highly conserved homologous (crossreactive) epitopes, or homotopes for short, are recognized by the natural immune system. Natural antibodies, LBP, and CRP are capable of activating the entire immune system after combination with the appropriate homotope. During febrile illness natural immune host defense is promptly elevated because of the rapid rise of natural antibodies, LBP, and CRP in the serum. This is known as the acute phase response (APR), which is initiated by a sudden rise of cytokines in the circulation, such as IL-1, IL-6, and TNF-alpha. The cytokines act on the brain, the neuroendocrine system, and on other tissues and organs, which leads to fever and profound hormonal and metabolic changes. The hypothalamus-pituitary adrenal axis is activated and serves as the primary regulator of immune and inflammatory reactions. Insulin, glucagon, and catecholeamine levels are also raised. Bone marrow activity and leukocyte function are high and the liver is converted to the rapid production of acute-phase proteins (APP). APP include LBP, CRP, fibrinogen, some complement components, enzyme inhibitors, and anti-inflammatory proteins, which may rise in the serum from several hundred to a thousand times within 24–48 hr. Therefore, natural immunity is a polyspecific response to homotopes, which functions as an instantaneous defense mechanism in health and which is rapidly boosted by cytokines and hormones during febrile illness. This is a highly successful defense reaction, as in the overwhelming majority of cases, febrile illness leads to recovery and the development of adaptive immunity in man and higher animals.

Dependence of proteoglycan induced arthritis in BALB/c mice on the development of autoantibodies to high density proteoglycans.

BALB/c mice were immunised with high or low density native human cartilage proteoglycans, or the respective core proteins obtained from chondroitin ABC lyase digestion. Mice injected with high density native proteoglycans developed arthritis whereas mice injected with low density proteoglycans or with core proteins did not. Analysis of the immune response by enzyme linked immunosorbent assay (ELISA) and western blot showed a stronger and more polyspecific response in animals injected with low density proteoglycans compared with mice with arthritis which had been injected with high density proteoglycans. Autoantibodies to mouse high density proteoglycans were only present in mice injected with native human high density proteoglycans, however. The data suggest that an arthritogenic epitope lies within the glycosaminoglycan rich region of the native proteoglycan molecule, which may induce an autoantibody response and subsequently arthritis in BALB/c mice.

Quantification of virus-specific antibodies in cerebrospinal fluid and serum: sensitive and specific detection of antibody synthesis in brain

Specific antibody synthesis in brain could be detected with maximal sensitivity by combining an advanced enzyme immunoassay with a sophisticated evaluation method that involves calculating the ratio between the cerebrospinal fluid (CSF)/serum quotients for specific antibodies (Qspec) and total IgG (QIgG). This Antibody Index (AI = Qspec/QIgG) discriminates between a blood-derived and a pathological, brain-derived specific antibody fraction in CSF and takes into account individual changes in blood/CSF barrier function. For local synthesis of polyclonal IgG in the central nervous system (QIgG greater than QLim), we propose the correction AI = Qspec/QLim (QLim represents that IgG fraction in CSF originating only from blood, calculated from the individual albumin quotient of a single patient). The normal reference range for the AI was between 0.7 and 1.3 (n = 250 control patients for each antibody species). Values of AI greater than or equal to 1.5 indicated a local specific antibody synthesis in the central nervous system. Sensitivity and precision were greatest if we analyzed the virus-specific antibodies in CSF and serum simultaneously with an enzyme immunoassay in continuous concentrations (arbitrary units) instead of titer steps. We have applied the method successfully to antibodies to measles, rubella, herpes simplex, varicella-zoster, human immunodeficiency virus (HIV), and cytomegalovirus, and to anti-Toxoplasma or -Borrelia antibodies. Clinical relevance is demonstrated for an acute zoster virus infection (monospecific response), chronic diseases such as HIV encephalitis with acute opportunistic Toxoplasma infection, and multiple sclerosis (secondary polyspecific response).

T cell activation of antigen-specific antibody responses by large B cells is MHC restricted.

The activation of small, resting B cells for antibody synthesis by helper T cells has been proposed to require an MHC-restricted interaction between the T and B cells. Large, activated B lymphocytes were, in contrast, thought to be activated by an unrestricted pathway. We re-examined this issue and found that both large and small size fractionated murine B lymphocytes required an MHC-restricted interaction with helper T cells to be activated for specific antibody synthesis. Polyspecific antibody synthesis in the same cultures was not dependent upon an MHC-restricted T-B interaction for any size category of B cell. These results are interpreted as reflecting the ability of antigen-specific B cells to focus and present antigen to T cells, in contrast to B cells of random specificity, which have no effective focusing mechanism for a given experimental antigen. We found that the polyspecific response required much higher antigen concentrations than the antigen-specific response, a result consistent with the antigen-focusing hypothesis.