Mechanism(s) of prolonged attenuation of allergic responses after modulation of idiotypic regulatory network

CpG adjuvant enhances humoral and cellular immunity against OVA in different degrees in BALB/c, C57BL/6J, and C57BL/6N mice

In lab settings, inbred mouse strains like BALB/c, C57BL/6J, and C57BL/6N are commonly used. Research in immunology and infectious diseases indicates that their Th1 and Th2 immune responses differ. However, the specific differences in the immune response to the vaccination still require investigation. In this study, ovalbumin (OVA) was used as an antigen and CpG-enriched recombinant plasmid (pUC18-CpG) as an adjuvant for immunisation. The level of serum-specific antibody IgG was detected by indirect ELISA. At 35dpi, serum cytokine levels were measured using MILLIPLEX®. T lymphocyte clusters from mouse spleen were examined using flow cytometry to investigate the immunological effects of the CPG-OVA vaccine on three different types of mice. The results showed that pUC18-CpG as an adjuvant could successfully enhance the immune response. BALB/c had the highest level of IgG antibody. In the OVA-only group, the CD4+/CD8+ ratio of the three types of mice was generally increased, and the BALB/c group had the highest ratio. After inoculation with CpG-OVA, the CD4+/CD8+ ratio of the three types of mice was lower than that of the OVA-only group, and C57BL/6J was the lowest. Compared with the CpG-OVA group of the three kinds of mice, the levels of Th2 cytokines IL-6 and IL-10 in BALB/c were increased compared with C57BL/6J and C57BL/6N. After OVA, the six cytokines secreted in C57BL/6J were higher than those in the C57BL/6N OVA group. Therefore, C57 is a better model for examining the function of the vaccine in cellular immunity, whereas BALB/c mice are more prone to humoral immunity. In addition to highlighting the CpG plasmid's ability to successfully activate the immune response of Th1 and Th2, as well as the expression of IgG in vivo and promote T cell immune typing, this study provides valuable insights into immunology and the selection of mouse models for infectious diseases, providing a valuable resource for designing more effective vaccines in the future.

Intravenous immunoglobulin for patients with unexplained recurrent implantation failure: a 6-year single center retrospective review of clinical outcomes

The effectiveness of intravenous immunoglobulin (IVIg) for patients with unexplained recurrent implantation failure (uRIF) remains debated. We retrospectively analysed outcomes of uRIF patients treated with IVIg compared to a separate control uRIF cohort within our center (01/2014-12/2021). Primary outcomes included live birth, miscarriage, or transfer failure. We documented IVIg side effects and maternal/fetal outcomes. Logistic regression analysis was used to assess for association of IVIg exposure with outcomes and adjust for confounders. The study included 143 patients, with a 2:1 ratio of controls to patients receiving IVIg treatment. Patient characteristics were similar between groups. There was higher live birth rate (LBR) in patients receiving IVIg (32/49; 65.3%) compared to controls (32/94; 34%); p < 0.001). When stratifying patients into moderate and severe uRIF (respectively 3-4 and [Formula: see text] 5 previous good quality blastocyst transfer failures), only patients with severe uRIF benefited from IVIg (LBR (20/29 (69%) versus 5/25 (20%) for controls, p = 0.0004). In the logistic regression analysis, IVIg was associated with higher odds of live birth (OR 3.64; 95% CI 1.78-7.67; p = 0.0004). There were no serious adverse events with IVIg. IVIg can be considered in well selected patients with [Formula: see text] 5 previous unexplained, high quality blastocyst transfer failures. A randomized controlled trial is needed to confirm these findings.

Immune modulation and possible pathological implications mediated by naturally produced immunoglobulin G idiotypes: from historical to recent experimental and clinical studies focused on atopic dermatitis

Since the 1950s decade, it has been suggested that a naturally produced or induced repertoire of immunoglobulin G (IgG) idiotypes may exert some immunoregulatory functions. In the last decades, some more advanced theories have suggested that the repertoire of IgG idiotypes may influence the development or control of some atopic diseases. In atopic dermatitis (AD), some evidence indicated that the IgG repertoire obtained from these patients could effectively mediate regulatory functions on thymic and peripheral CD4+ and CD8+ T cells. Furthermore, some recent clinical trials have corroborated the hypothesis that IgG from AD patients can exert regulatory functions in vivo. Here, we revised some historical aspects that yield current approaches developed in vitro and in vivo to elucidate a recently proposed theory termed "hooks without bait" that can strengthen the broad spectrum of research about evaluating different sets of IgG idiotypes and determine their immunological effects.

Intravenous immunoglobulin use in patients with unexplained recurrent pregnancy loss

PROBLEM

Recurrent pregnancy loss (RPL) affects up to 4% of couples attempting to conceive. RPL is unexplained in over 50% of cases and no effective treatments exist. Due to the immune system's pivotal role during implantation and pregnancy, immune-mediated RPL may be suspected and immunomodulatory treatments like intravenous immunoglobulin (IVIg) have been administered but remain controversial. The goal of our study was to evaluate our center's 6 year-outcomes and to develop a framework for IVIg use in RPL.

METHOD OF THE STUDY

Retrospective, single-center cohort study. All patients having received IVIg for unexplained RPL at the McGill Reproductive Immunology Clinic (MRIC) from January 2014 to December 2020 were included if maternal age was <42 years, body mass index (BMI) < 35 kg/m² , non-smoker and having had ≥3 consecutive RPL despite previous treatment with aspirin and progesterone. IVIg 0.6-0.8 g/kg was given prior to conception and monthly during pregnancy until 16-20 weeks' gestation. We compared IVIg treated patient's outcomes to a separate "natural history cohort". This cohort was composed of patients consulting at the McGill recurrent pregnancy loss clinic and the MRIC over a 2-year period (January 2020 to December 2021) with similar inclusion criteria as the treatment cohort but did not receive IVIg or other immunomodulatory treatments. The association of IVIg with outcomes (compared to no IVIg) was evaluated among the groups of patients with primary RPL and secondary RPL. The primary outcome was live birth rate (LBR), secondary outcomes included IVIg safety, obstetrical, and neonatal complications.

RESULTS

Among 169 patients with unexplained RPL that were included in the study, 111 had primary RPL (38 exposed to IVIg and 83 controls) and 58 had secondary RPL (nine exposed to IVIG and 49 controls). Among patients with primary RPL (n = 111), the LBR was 64.3% (18/28) among patient exposed to IVIg compared to 43.4% (36/83) in controls (p = 0.079); regression analysis adjusting for BMI and number of previous miscarriages showed benefit favoring the use of IVIg (OR = 3.27, CI 95% (1.15-10.2), p = 0.03) when evaluating for live birth. In the subgroup of patients with ≥5 previous RPL and primary RPL (n = 31), IVIg was associated with higher LBR compared to control (10/15 (66.7%) vs. 3/16 (18.8%); p = 0.0113) but not the in the sub-group of patients with <5 miscarriages and primary RPL (8/13 (61.5%) vs. 33/67 (49.3%); p = 0.548). IVIG treatment did not improve LBR in patients with secondary RPL in our study (3/9 (33.3%) vs. 23/49 (47%); p = 0.495). There were no serious adverse events in the IVIg treatment group, obstetrical/neonatal complications were similar between groups.

CONCLUSION

IVIg may be an effective treatment for patients with RPL if appropriately used in specific groups of patients. IVIg is a blood product and subject to shortages especially with unrestricted off-label use. We propose considering IVIg in well-selected patients with high order RPL who have failed standard medical therapy. Further mechanistic studies are needed to understand immune-mediated RPL and IVIg's mode of action. This will enable further refinement of treatment criteria and the development of standardized protocol for its use in RPL.

Lactobacillus paragasseri BBM171 Ameliorates Allergic Airway Inflammation Induced by Ovalbumin in Mice via Modulating the Th1/Th2 Balance

Supplementation with specific probiotics has been shown to improve allergic airway symptoms. This study aimed to investigate immunomodulatory effects of a potential probiotic strain isolated from breast milk, Lactobacillus paragasseri BBM171 (BBM171), in an ovalbumin (OVA)-induced allergic mouse model. OVA-sensitized and OVA-challenged BALB/c mice were orally administered live or heat-inactivated BBM171 for 48 consecutive days. After the last allergen challenge, serum immunoglobulin (Ig) levels, inflammatory cell levels in the lungs, and cytokine levels in bronchoalveolar lavage fluid (BALF) were assessed. The results showed that oral administration of live or heat-inactivated BBM171 decreased serum levels of total IgE, OVA-specific IgE, and OVA-specific IgG1, while increasing OVA-specific IgG2a and reducing the extent of airway inflammation in OVA-induced allergic mice. In addition, both live and heat-inactivated BBM171 modulated the cytokine profile in BALF to a type 1 T helper (Th1) response. Furthermore, ex vivo experiments using OVA-induced allergic mouse splenocytes showed that both live and heat-inactivated BBM171 could regulate the Th1/Th2 balance, decrease the proinflammatory cytokine interleukin (IL)-17 level, and increase the anti-inflammatory cytokine IL-10 level. Taken together, these results suggest that oral administration of live or heat-inactivated BBM171 improved allergen-induced airway inflammation symptoms by modulating the host immune response toward Th1 dominance.

Toward a fractalomic idiotype/anti-idiotypic paradigm

The CoViD-19 pandemic has demonstrated the need for future developments in anti-viral immunology. We propose that artificial intelligence (AI) and machine learning, and in particular fractal analysis could play a crucial role in that context. Fractals - never-ending repeats of self-similar shapes whose composite tend to resemble the whole - are found in most natural biological structures including immunoglobulin and antigenic epitopes. Increased knowledge of the fractalomic properties of the idiotype/anti-idiotypic paradigm should help develop a novel and improved simplified artificial model of the immune system. Case in point, the regulation and dampening of antibodies as well as the synergetic recognition of an antigen by multiple idiotypes are both immune mechanisms that require further analysis. An enhanced understanding of these complexities could lead to better data analysis for novel vaccines to improve their sensitivity and specificity as well as open other new doors in the field of immunology.

Anti-ST2 Nanoparticle Alleviates Lung Inflammation by Targeting ILC2s-CD4+T Response

Background

Asthma has been regarded as an inflammatory disease, and group 2 innate lymphoid cells (ILC2s) are implicated in asthma pathogenesis. However, no strategy is available to block ILC2s function. Efficiency is also limited due to the use of systemic or subcutaneous routes of administration. The purpose of this study was to investigate the effects of nanoparticles targeting suppression of tumorigenicity 2 (ST2), which is the ILC2 receptor, to alleviate lung inflammation in the murine model of asthma.

Methods

The ultra-small SPIO nanoparticles were firstly synthesized, OVA-induced mice were administered by anti-ST2-conjugated nanoparticles. The inflammatory degree of the lung was investigated by H&E. The percentages of ILC2s and CD4⁺T cells in bronchoalveolar lavage fluid (BALF) and lung tissue were determined by FACS. Th2-cytokine and OVA-IgE levels were detected by real-time PCR and ELISA, respectively.

Results

Treatment with anti-ST2-conjugated nanoparticles significantly alleviated airway inflammation, IL-33 and IL-13 levels and the percentage of CD4⁺T cells. The percentage of ILC2s was increased, whereas the levels of IL-13 and IL-5 expressed by ILC2s were reduced.

Conclusion

In the present study, we demonstrated that anti-ST2-conjugated nanoparticles can efficiently control lung inflammation in OVA-induced mice by reducing the ability of ILC2s to produce IL-5 and IL-13, thereby reducing CD4+T cells. Our study also demonstrated that the nanoparticle delivery system could improve the performance of anti-ST2, which may be used as a strategic tool to expand the current drug market.

Regulatory T cells mediated immunomodulation during asthma: a therapeutic standpoint

Asthma is an inflammatory disease of the lung airway network, which is initiated and perpetuated by allergen-specific CD4⁺ T cells, IgE antibodies, and a massive release of Th2 cytokines. The most common clinical manifestations of asthma progression include airway inflammation, pathological airway tissue and microvascular remodeling, which leads to airway hyperresponsiveness (AHR), and reversible airway obstruction. In addition to inflammatory cells, a tiny population of Regulatory T cells (Tregs) control immune homeostasis, suppress allergic responses, and participate in the resolution of inflammation-associated tissue injuries. Preclinical and clinical studies have demonstrated a tremendous therapeutic potential of Tregs in allergic airway disease, which plays a crucial role in immunosuppression, and rejuvenation of inflamed airways. These findings supported to harness the immunotherapeutic potential of Tregs to suppress airway inflammation and airway microvascular reestablishment during the progression of the asthma disease. This review addresses the therapeutic impact of Tregs and how Treg mediated immunomodulation plays a vital role in subduing the development of airway inflammation, and associated airway remodeling during the onset of disease.

Do different IgG repertoires play a role in B- and T-cell functional modulation during ontogeny? The "hooks without bait" theory

The mechanisms by which immunoglobulin (Ig)G can modulate immunity have been investigated over the past few decades. In the past three years, some studies have demonstrated that IgG can play a pivotal role in mediating complex interactions that result in functional lymphocyte modulation during maturation in self or offspring primary lymphoid organs. This effect appears to be dependent on the IgG repertoire in the absence of the influence of antigens and the functionality of diverse cell populations, including B, αβT (CD4 T and CD8 T), invariant natural killer T and γδT cells, in mice and humans. Based on the literature, especially on findings resulting from the therapeutic use of purified IgG (intravenous Ig) and recent pieces of evidence obtained by my group, the "hooks without bait" theory is described here to guide the future development of therapies for specific immune regulation.

Combined IMIG and Immune Ig Attenuate Allergic Responses in Beagle Dogs

Background

We previously reported attenuation of serum OVA-specific IgE levels and of lymphocyte-derived IL-4, both nominal markers of allergic immunity, following injection of a combination of homologous (mouse) polyclonal anti-idiotypic immunoglobulin (Ig) and immune Ig in BALB/c mice. We predicted this might generalize to other species and using heterologous mixtures of Igs. This was assessed in mice using OVA sensitization in the presence of human Igs as a source of both anti-idiotype Ig and immune Ig and in dogs with peanut butter-induced allergic responses.

Methods

Eight-week-old BALB/c mice received OVA immunization and 5 weekly injections of immune Ig or anti-idiotype Ig from either homologous (mouse) or heterologous (human) sources. Five-month-old Beagles received weekly topical exposure (on the abdomen) to peanut butter and treatment with pooled dog Ig and dog antirabies immune Ig, or a combination of human IMIG and human anti-Tet. All mice/dogs thereafter received a final allergen challenge, and serum IgG, IgE, and allergen-induced IL-2/IL-4 and IL-31 production in 72 hr cultures was measured.

Results

In mice attenuation of OVA-induced allergy (IgE-specific Ig and OVA-induced IL-4) was seen using both mouse and human Ig mixtures, without effect on OVA serum IgG or OVA-induced IL-2. Attenuation of concanavalin A- (ConA-) induced IL-4 : IL-2 production and of peanut butter-induced IL-4 and IL-31 was seen in dogs receiving combinations of both heterologous and homologous immune Igs and anti-idiotype Igs, with no decline in IL-2 production. Allergen-specific IgE/IgG was not detectable in dog serum, but there was a trend to lower total serum IgE levels (and decreased IgE : IgG ratios).

Conclusion

Homologous and heterologous combinations of polyclonal IMIG and immune Ig attenuate allergic responses in mice and dogs. This treatment protocol represents a novel approach which can be adapted for allergic desensitization in veterinary and human use.

Combined IMIG and immune Ig attenuates inflammatory colitis in mice

BACKGROUND

Using a combination of homologous and heterologous (mouse/human) polyclonal anti-idiotypic Igs and immune Igs in BALB/c mice we have previously reported attenuation of allergic type responses following OVA immunization. We have now investigated attenuation of an inflammatory colitis in C57BL/6 mice receiving dextran sodium sulfate (DSS) in their drinking water, using additional treatment of DSS-exposed mice with combined human Igs, commercial IVIG (given IM, hence hereafter IMIG) as a source of pooled anti-idiotype Ig, and human anti-Tet as immune Ig.

METHODS

Acute or chronic colitis was induced by DSS in groups of C57BL/6 mice. Mice also received weekly immunotherapy with im injections of polyclonal immune Ig, polyclonal anti-idiotype Ig, or the combined Igs, for a total of 5 injections, beginning with DSS treatment or after 2 cycles of DSS. Weight loss and mortality were monitored daily, and the extent of colitis was determined further using colonic length measurement, and by ELISA measurement of inflammatory cytokines in supernatants from colonic explant cultures.

RESULTS

Mice developed colitis in both the acute and chronic models with loss of body weight, shortened colon lengths, and increased expression of inflammatory cytokines in colonic tissue. Loss of body weight, and inflammatory cytokine production, was attenuated only in chronic colitis, and only after combined IMIG and immune Ig treatment, and not in groups receiving only IMIG or immune Ig alone.

CONCLUSION

Heterologous combinations of polyclonal IMIG and immune Ig can attenuate inflammatory colitis in mice. Given the described efficacy of this treatment for allergic desensitization, we hypothesize this methodology may have widespread clinic utility.