Preparation of commercial quantities of a hyperimmune human intravenous immunoglobulin preparation against an emerging infectious disease: the example of pandemic H1N1 influenza

Passive immunotherapies for the next influenza pandemic

Influenzavirus is among the most relevant candidates for a next pandemic. We review here the phylogeny of former influenza pandemics, and discuss candidate lineages. After briefly reviewing the other existing antiviral options, we discuss in detail the evidences supporting the efficacy of passive immunotherapies against influenzavirus, with a focus on convalescent plasma.

Virus Neutralization by Human Intravenous Immunoglobulin Against Influenza Virus Subtypes A/H5 and A/H7

Purpose

Highly pathogenic avian influenza viruses are a threat to human health. Although donor populations have not experienced pandemic, they have been immunized by natural infections and/or vaccinations of influenza viruses such as A/H1N1, A/H3N2, and B. Therefore, it is considered that human intravenous immunoglobulin (IVIG) derived from healthy donors does not include IgG against avian influenza viruses. However, cross-reactivity has not been evaluated yet. In this study, cross-reactivity against the avian influenza virus A/H5N1, A/H7N1, A/H7N2, A/H7N7, A/H7N9, and A/H10N9 was evaluated.

Materials and Methods

Several lots of IVIG derived from healthy donors in Japan were tested for virus neutralization using single- or multi-cycle virus neutralizing (S-VN or M-VN) assays that evaluate the infection-step associated with HA or the infection and propagation steps associated with HA and NA, respectively. In addition, anti-NA activities were evaluated by inhibiting the enzymatic activity in NAI assays.

Results

IVIG lots showed high neutralizing activities against three A/H5N1 strains in M-VN assays, whereas activities in S-VN assays were unstable. In addition, A/H7N2 was also neutralized in S-VN and M-VN assays, with higher activity in M-VN than in S-VN assays. A/H7N1 was neutralized in S-VN and M-VN assays. In contrast, weak or no activity against A/H7N7, A/H7N9, and A/H10N9 was observed in S-VN and M-VN assays. NAI assay results show that IVIG lots had inhibitory activities against N1 and N2; however, N2 activities differed depending on the strain. In contrast, no activities were observed against N7 and N9.

Conclusion

These results suggest that IVIG lots have neutralizing activity against avian influenza viruses during the virus propagation step, except for one strain, although no or weak activity was observed during the infection step.

COVID-19 preparedness: capacity to manufacture vaccines, therapeutics and diagnostics in sub-Saharan Africa

OBJECTIVE

The COVID-19 pandemic is a biosecurity threat, and many resource-rich countries are stockpiling and/or making plans to secure supplies of vaccine, therapeutics, and diagnostics for their citizens. We review the products that are being investigated for the prevention, diagnosis, and treatment of COVID-19; discuss the challenges that countries in sub-Saharan Africa may face with access to COVID-19 vaccine, therapeutics, and diagnostics due to the limited capacity to manufacture them in Africa; and make recommendations on actions to mitigate these challenges and ensure health security in sub-Saharan Africa during this unprecedented pandemic and future public-health crises.

MAIN BODY

Sub-Saharan Africa will not be self-reliant for COVID-19 vaccines when they are developed. It can, however, take advantage of existing initiatives aimed at supporting COVID-19 vaccine access to resource-limited settings such as partnership with AstraZeneca, the Coalition for Epidemic Preparedness and Innovation, the Global Alliance for Vaccine and Immunisation, the Serum Institute of India, and the World Health Organization's COVID-19 Technology Access Pool. Accessing effective COVID-19 therapeutics will also be a major challenge for countries in sub-Saharan Africa, as production of therapeutics is frequently geared towards profitable Western markets and is ill-adapted to sub-Saharan Africa realities. The region can benefit from pooled procurement of COVID-19 therapy by the Africa Centres for Disease Control and Prevention in partnership with the African Union. If the use of convalescent plasma for the treatment of patients who are severely ill is found to be effective, access to the product will be minimally challenging since the region has a pool of recovered patients and human resources that can man supportive laboratories. The region also needs to drive the local development of rapid-test kits and other diagnostics for COVID-19.

CONCLUSION

Access to vaccines, therapeutics, and diagnostics for COVID-19 will be a challenge for sub-Saharan Africans. This challenge should be confronted by collaborating with vaccine developers; pooled procurement of COVID-19 therapeutics; and local development of testing and diagnostic materials. The COVID-19 pandemic should be a wake-up call for sub-Saharan Africa to build vaccines, therapeutics, and diagnostics manufacturing capacity as one of the resources needed to address public-health crises.

Convalescent Plasma Therapy for Management of COVID-19: Perspectives and Deployment in the Current Global Pandemic

The world is striving against the severe crisis of the COVID-19 pandemic. Healthcare professionals are struggling to treat their patients based on nonspecific therapies. Amidst this uncertainty, convalescent plasma therapy (CPT) has appeared to be an interim adjuvant therapy for severely ill patients of COVID-19 until long-term clinical trial treatment options are available. Considering the transfusion-related hazards, especially lung injuries and microbial transmission, where sensitivity is not ensured, rigorous trials should be conducted to determine this therapy's efficacy. Moreover, the ratio of recovered cases to plasma donors is not satisfying, which questioning this therapy's availability and accessibility. Although some countries are making the treatment free, the attributable cost mandates a justification for its suitability and sustainability. Our article aimed to review the published facts and findings of CPT's effectiveness in lowering the mortality rate of COVID-19. This pandemic showed that healthcare systems worldwide need core reform. A unified global collaboration must align and coordinate to face the current pandemic and enhance world readiness for future outbreaks based on health equity and equality.

Specificity, kinetics and longevity of antibody responses to avian influenza A(H7N9) virus infection in humans

OBJECTIVES

The long-term dynamics of antibody responses in patients with influenza A(H7N9) virus infection are not well understood.

METHODS

We conducted a longitudinal serological follow-up study in patients who were hospitalized with A(H7N9) virus infection, during 2013-2018. A(H7N9) virus-specific antibody responses were assessed by hemagglutination inhibition (HAI) and neutralization (NT) assays. A random intercept model was used to fit a curve to HAI antibody responses over time. HAI antibody responses were compared by clinical severity.

RESULTS

Of 67 patients with A(H7N9) virus infection, HAI antibody titers reached 40 on average 11 days after illness onset and peaked at a titer of 290 after three months, and average titers of ≥80 and ≥40 were present until 11 months and 22 months respectively. HAI antibody responses were significantly higher in patients who experienced severe disease, including respiratory failure and acute respiratory distress syndrome, compared with patients who experienced less severe illness.

CONCLUSIONS

Patients with A(H7N9) virus infection who survived severe disease mounted higher antibody responses that persisted for longer periods compared with those that experienced moderate disease. Studies of convalescent plasma treatment for A(H7N9) patients should consider collection of donor plasma from survivors of severe disease between 1 and 11 months after illness onset.

Efficacy of anti-influenza immunoglobulin (FLU-IGIV) in ferrets and mice infected with 2009 pandemic influenza virus

Seasonal influenza causes significant morbidity and mortality around the world each year, even with the use of vaccines and antivirals. There is a need for more effective treatments for severe and hospitalized cases of influenza. In this study, we have tested the efficacy of a human plasma-derived IgG product (FLU-IGIV) against seasonal influenza in mouse and ferret models of influenza infection. FLU-IGIV successfully protected mice (100% survival) against lethal influenza infection. Also, the survival rate observed with FLU-IGIV treatment was better than the survival rate observed with oseltamivir (60% survival). FLU-IGIV significantly reduced the viral load in the lungs compared to placebo (PBS) in ferrets infected with influenza A/California/07/2009 (H1N1pdm09) virus. Overall, these studies demonstrate the efficacy of human plasma-derived FLU-IGIV in relevant animal models of influenza virus infection.

Treatment-donation-stockpile dynamics in ebola convalescent blood transfusion therapy

The interim guidance issued by the World Health Organization during the West Africa 2014 Ebola outbreak provides guidelines on the use of convalescent blood from Ebola survivors for transfusion therapy. Here we develop a novel mathematical model, based on the interim guidance, to examine the nonlinear transmission–treatment–donation–stockpile dynamics during an Ebola outbreak and with a large scale use of the transfusion therapy in the population. We estimate the reduction of case fatality ratio by introducing convalescent blood transfusion as a therapy, and inform optimal treatment–donation–stockpile strategies to balance the treatment need for case fatality ratio reduction and the strategic need of maintaining a minimal blood bank stockpile for other control priorities.

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A novel model for the large-scale use of the convalescent blood transfusion therapy.

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Based on WHO׳s interim convalescent treatment guidance in 2014 Ebola outbreak.

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Estimate the reduction of case fatality ratio by introducing convalescent therapy.

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Inform optimal treatment-donation-stockpile strategies.

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Guide convalescent blood transfusion services in future emerging disease outbreaks.

Plasma therapy against infectious pathogens, as of yesterday, today and tomorrow

Plasma therapy consists in bringing to a patient in need - in general suffering a severe, resistant to current therapy, and even lethal infection - plasma or specific, fractioned, antibodies, along with other immunoglobulins and possibly healing factors that can be obtained from immunized blood donors; donors (voluntary and benevolent) can be either actively immunized individuals or convalescent persons. Plasma therapy has been used since the Spanish flu in 1917-1918, and regularly then when viral epidemics threatened vulnerable populations, the last reported occurrence being the 2013-2015 Ebola virus outbreak in West Africa. The precise action mechanism of plasma therapy is not fully delineated as it may function beyond purified, neutralizing antibodies.

Treatment of Ebola virus infection with antibodies from reconvalescent donors

Clinical evidence suggests that antibodies from reconvalescent donors (persons who have recovered from infection) may be effective in the treatment of Ebola virus infection. Administration of this treatment to Ebola virus–infected patients while preventing the transmission of other pathogenic viruses may be best accomplished by use of virus-inactivated reconvalescent plasma.

Structural characterization of a protective epitope spanning A(H1N1)pdm09 influenza virus neuraminidase monomers

A(H1N1)pdm09 influenza A viruses predominated in the 2013–2014 USA influenza season, and although most of these viruses remain sensitive to Food and Drug Administration-approved neuraminidase (NA) inhibitors, alternative therapies are needed. Here we show that monoclonal antibody CD6, selected for binding to the NA of the prototypic A(H1N1)pdm09 virus, A/California/07/2009, protects mice against lethal virus challenge. The crystal structure of NA in complex with CD6 Fab reveals a unique epitope, where the heavy-chain complementarity determining regions (HCDRs) 1 and 2 bind one NA monomer, the light-chain CDR2 binds the neighbouring monomer, whereas HCDR3 interacts with both monomers. This 30-amino-acid epitope spans the lateral face of an NA dimer and is conserved among circulating A(H1N1)pdm09 viruses. These results suggest that the large, lateral CD6 epitope may be an effective target of antibodies selected for development as therapeutic agents against circulating H1N1 influenza viruses.

Neuraminidase inhibitors offer a line of defence against flu infections, but resistance can occur even in the absence of prior exposure. Here Wan et al. describe the mode of action of CD6, a monoclonal antibody that protects against a common influenza strain, as a new therapeutic intervention model.

Cross-reactive influenza-specific antibody-dependent cellular cytotoxicity in intravenous immunoglobulin as a potential therapeutic against emerging influenza viruses

BACKGROUND

Intravenous immunoglobulin (IVIG) is a purified pool of human antibodies from thousands of donors that is used to prevent or treat primary immune deficiency, several infectious diseases, and autoimmune diseases. The antibodies that mediate antibody-dependent cellular cytotoxicity (ADCC) against heterologous influenza strains may be present in IVIG preparations.

METHODS

We tested 8 IVIG preparations prior to the 2009 H1N1 swine-origin influenza pandemic and 10 IVIG preparations made after 2010 for their ability to mediate influenza-specific ADCC.

RESULTS

ADCC mediating antibodies to A(H1N1)pdm09 hemagglutinin (HA) and neuraminidase (NA) were detected in IVIG preparations prior to the 2009-H1N1 pandemic. The HA-specific ADCC targeted both the HA1 and HA2 regions of A(H1N1)pdm09 HA and was capable of recognizing a broad range of HA proteins including those from recent avian influenza strains A(H5N1) and A(H7N9). The low but detectable ADCC recognition of A(H7N9) was likely due to rare individuals in the population contributing cross-reactive antibodies to IVIG.

CONCLUSIONS

IVIG preparations contain broadly cross-reactive ADCC mediating antibodies. IVIG may provide at least some level of protection for individuals at high risk of severe influenza disease, especially during influenza pandemics prior to the development of effective vaccines.

Hyperimmune intravenous immunoglobulin containing high titers of pandemic H1N1 hemagglutinin and neuraminidase antibodies provides dose-dependent protection against lethal virus challenge in SCID mice

Background

Convalescent plasma and fractionated immunoglobulins have been suggested as prophylactic or therapeutic interventions during an influenza pandemic.

Findings

Intravenous immunoglobulin (IVIG) preparations manufactured from human plasma collected before the 2009 H1N1 influenza pandemic, and post-pandemic hyperimmune (H)-IVIG preparations were characterized with respect to hemagglutination inhibition (HI), microneutralization (MN) and neuraminidase-inhibiting (NAi) antibody titers against pandemic H1N1 (pH1N1) and seasonal H1N1 (sH1N1) viruses. The protective efficacy of the IVIG and H-IVIG preparations was evaluated in a SCID mouse challenge model.

Substantial levels of HI, MN and NAi antibodies against pH1N1 (GMTs 1:45, 1:204 and 1: 727, respectively) and sH1N1 (GMTs 1:688, 1:4,946 and 1:312, respectively) were present in pre-pandemic IVIG preparations. In post-pandemic H-IVIG preparations, HI, MN and NAi antibody GMTs against pH1N1 were 1:1,280, 1:11,404 and 1:2,488 (28-, 56- and 3.4-fold enriched), respectively, compared to pre-pandemic IVIG preparations (p < 0.001). Post-pandemic H-IVIG (HI titer 1:1,280) provided complete protection from lethality of SCID mice against pH1N1 challenge (100% of mice survived for 29 days post-challenge). Pre-pandemic IVIG (HI titer 1:70) did not provide significant protection against pH1N1 challenge (50% of mice survived 29 days post-challenge compared to 40% survival in the buffer control group). There was a highly significant correlation between circulating in vivo HI and MN antibody titers and survival (p < 0001).

Conclusion

The substantial enrichment of HA- and NA-specific antibodies in H-IVIG and the efficacious protection of SCID mice against challenge with pH1N1 suggests H-IVIG as a promising intervention against pandemic influenza for immunocompromised patients and other risk groups.

New Wisdom to Defy an Old Enemy: Summary from a scientific symposium at the 4th Influenza Vaccines for the World (IVW) 2012 Congress, 11 October, Valencia, Spain

Both seasonal and pandemic influenza cause considerable morbidity and mortality globally. In addition, the ongoing threat of new, unpredictable influenza pandemics from emerging variant strains cannot be underestimated. Recently bioCSL (previously known as CSL Biotherapies) sponsored a symposium 'New Wisdom to Defy an Old Enemy' at the 4th Influenza Vaccines for the World Congress in Valencia, Spain. This symposium brought together a renowned faculty of experts to discuss lessons from past experience, novel influenza vaccine developments, and new methods to increase vaccine acceptance and coverage. Specific topics reviewed and discussed included new vaccine development efforts focused on improving efficacy via alternative administration routes, dose modifications, improved adjuvants, and the use of master donor viruses. Improved safety was also discussed, particularly the new finding of an excess of febrile reactions isolated to children who received the 2010 Southern Hemisphere (SH) trivalent inactivated influenza vaccine (TIV). Significant work has been done to both identify the cause and minimize the risk of febrile reactions in children. Other novel prophylactic and therapeutic advances were discussed including immunotherapy. Standard IVIg and hIVIg have been used in ferret studies and human case reports with promising results. New adjuvants, such as ISCOMATRIX™ adjuvant, were noted to provide single-dose, prolonged protection with seasonal vaccine after lethal H5N1 virus challenge in a ferret model of human influenza disease. The data suggest that adjuvanted seasonal influenza vaccines may provide broader protection than unadjuvanted vaccines. The use of an antigen-formulated vaccine to induce broad protection between pandemics that could bridge the gap between pandemic declaration and the production of a homologous vaccine was also discussed. Finally, despite the availability of effective vaccines, most current efforts to increase influenza vaccine coverage rates to higher levels (i.e., above 70-80%) have been ineffective in highly developed countries where the vaccine is used, hindered by the public's skepticism towards vaccines in general. New educational and social media methods to increase vaccine acceptance and coverage were discussed. While the first priority should be the development of improved influenza vaccines, a particular focus on the aging global population is critical. It is also important to draw lessons from other academic disciplines that can help to inform vaccine education programs, policy, and communication. By tailoring communications and patient education using an understanding of cognitive bias and the model of preferred cognitive styles, the likelihood of effecting desirable health decisions can be maximized, leading to improved vaccine coverage and control of influenza and other vaccine-preventable diseases.

Physiological level production of antigen-specific human immunoglobulin in cloned transchromosomic cattle

Therapeutic human polyclonal antibodies (hpAbs) derived from pooled plasma from human donors are Food and Drug Administration approved biologics used in the treatment of a variety of human diseases. Powered by the natural diversity of immune response, hpAbs are effective in treating diseases caused by complex or quickly-evolving antigens such as viruses. We previously showed that transchromosomic (Tc) cattle carrying a human artificial chromosome (HAC) comprising the entire unrearranged human immunoglobulin heavy-chain (hIGH) and kappa-chain (hIGK) germline loci (named as κHAC) are capable of producing functional hpAbs when both of the bovine immunoglobulin mu heavy-chains, bIGHM and bIGHML1, are homozygously inactivated (double knockouts or DKO). However, B lymphocyte development in these Tc cattle is compromised, and the overall production of hpAbs is low. Here, we report the construction of an improved HAC, designated as cKSL-HACΔ, by incorporating all of the human immunoglobulin germline loci into the HAC. Furthermore, for avoiding the possible human-bovine interspecies incompatibility between the human immunoglobulin mu chain protein (hIgM) and bovine transmembrane α and β immunoglobulins (bIgα and bIgβ) in the pre-B cell receptor (pre-BCR) complex, we partially replaced (bovinized) the hIgM constant domain with the counterpart of bovine IgM (bIgM) that is involved in the interaction between bIgM and bIgα/Igβ; human IgM bovinization would also improve the functionality of hIgM in supporting B cell activation and proliferation. We also report the successful production of DKO Tc cattle carrying the cKSL-HACΔ (cKSL-HACΔ/DKO), the dramatic improvement of B cell development in these cattle and the high level production of hpAbs (as measured for the human IgG isotype) in the plasma. We further demonstrate that, upon immunization by tumor immunogens, high titer tumor immunogen-specific human IgG (hIgG) can be produced from such Tc cattle.