Idiotopes of antibodies against HIV-1 CD4-induced epitope shared with those against microorganisms.

Induction of antibodies (Abs) against the conformational CD4-induced (CD4i) epitope is frequent in HIV-1 infection. However, the mechanism of development of anti-CD4i Abs is unclear. We used anti-idiotypic (aID) monoclonal Abs (mAbs) of anti-CD4i mAbs to isolate anti-CD4i mAbs from infected subjects and track the causative antigens. One anti-aID mAb sorted from infected subjects by aID mAbs had the characteristics of anti-CD4i Abs, including IGHV1-69 usage and ability to bind to HIV-1 Env enhanced by sCD4. Critical amino acid sequences for the binding of six anti-aID mAbs, with shared idiotope to anti-CD4i mAbs, were analysed by phage display. The identified amino acid sequences showed similarity to proteins from human microbiota and infectious agents. Peptides synthesized from Caudoviricetes sp and Vibrio vulnificus based on the identified sequences were reactive to most anti-aID and some anti-CD4i mAbs. These results suggest that anti-CD4i Abs may evolve from B cells primed by microorganisms.

Functional analysis of a monoclonal antibody reactive against the C1C2 of Env obtained from a patient infected with HIV-1 CRF02_AG.

BACKGROUND: Recent data suggest the importance of non-neutralizing antibodies (nnAbs) in the development of vaccines against HIV-1 because two types of nnAbs that recognize the coreceptor binding site (CoRBS) and the C1C2 region mediate antibody-dependent cellular-cytotoxicity (ADCC) against HIV-1-infected cells. However, many studies have been conducted with nnAbs obtained from subtype B-infected individuals, with few studies in patients with non-subtype B infections. RESULTS: We isolated a monoclonal antibody 1E5 from a CRF02_AG-infected individual and constructed two forms of antibody with constant regions of IgG1 or IgG3. The epitope of 1E5 belongs to the C1C2 of gp120, and 1E5 binds to 27 out of 35 strains (77 %) across the subtypes. The 1E5 showed strong ADCC activity, especially in the form of IgG3 in the presence of small CD4-mimetic compounds (CD4mc) and 4E9C (anti-CoRBS antibody), but did not show any neutralizing activity even against the isolates with strong binding activities. The enhancement in the binding of A32, anti-C1C2 antibody isolated from a patient with subtype B infection, was observed in the presence of 1E5 and the combination of 1E5, A32 and 4E9C mediated a strong ADCC activity. CONCLUSIONS: These results suggest that anti-C1C2 antibodies that are induced in patients with different HIV-1 subtype infections have common functional modality and may have unexpected interactions. These data may have implications for vaccine development against HIV-1.

Addition of maraviroc to antiretroviral therapy decreased interferon-γ mRNA in the CD4+ T cells of patients with suboptimal CD4+ T-cell recovery.

The CCR5 antagonist, maraviroc (MVC), is associated with an enhanced CD4+ T-cell response independent of virological suppression; however, its mechanism of action has not been elucidated. In this study, we confirmed the effect of MVC on CD4+ T-cell count recovery in immunological non-responders, and compared the conventional combination antiretroviral therapy (cART) with MVC-intensified cART. We also investigated the effect of MVC on interferon-γ (IFN-γ) production in CD4+ T cells in vitro and in vivo, and evaluated the relationship between the mRNA level of IFN-γ and the degree of CD4+ T-cell count recovery. In vitro analysis indicated that MVC significantly decreased mRNA levels of IFN-γ in HIV-Tat stimulated CD4+ T cells from healthy donor peripheral blood mononuclear cells. Of the 18 HIV-infected patients treated with MVC-intensified cART, 12 had a significantly increased CD4+ T-cell count after 24 weeks of additional treatment with MVC. In patients exhibiting a response in CD4+ T-cell counts, mRNA levels of IFN-γ in CD4+ T cells were lower than those in patients showing a non-response at baseline and at week 24, while mRNA levels of IFN-γ decreased in both groups at 24 weeks. In conclusion, MVC decreased the mRNA level of IFN-γ in CD4+ T cells in vitro and in vivo, especially in patients whose CD4+ T-cell count increased significantly. We also found that the lower baseline IFN-γ mRNA level and the larger decreased rate of IFN-γ mRNA in CD4+ T cells were associated with a good response to MVC regarding CD4+ T-cell recovery.

[The Usefulness of the Scan with 67Ga-citrate to Assess the Therapeutic Effect on Pneumocystis pneumonia with HIV-1 Infection].

OBJECTIVE: Peumocystis pneumonia (PCP) is one of the common opportunistic infections with severe respiratory failure, and is sometimes life-threatening in patients with the acquired immunodeficiency syndrome. Although treatment for PCP is established, an appropriate treatment period has not been evaluated to clarify the risk factors for immune reconstitution inflammatory syndrome (IRIS) associated with PCP. METHOD: We retrospectively analyzed the clinical characteristics of risk factor, which are the treatment period for PCP, and 67Ga scintigraphy (Ga-S) at the 21st day from the start of the treatment for PCP, with 21 cases of PCP and HIV infection treated during 2005-2012 at Kyushu Medical Center. RESULT: The rate of residual uptake by Ga-S was assessed in 17 cases (81%). Four cases were diagnosed as being PCP-IRIS, and residual uptake by Ga-S was detected in all PCP-IRIS cases. The durations of the therapy were classified into three groups: 21 days, 28 days, and 35 days. All PCP-IRIS cases were treated in the period of 28 days. In contrast, in 11 cases that showed residual uptake by Ga-S, and were treated for PCP in 35 days, PCP-IRIS did not occur. Additionally, there were 4 cases in which residual uptake by Ga-S did not occur. They were treated with PCP for only 21 days, but did not show PCP-IRIS. CONCLUSION: In this study, we showed that Ga-S is useful to evaluate the therapeutic effect. Furthermore, we found that the occurrence of PCP-IRIS could be prevented with the early start of cART after 21 days treatment for PCP, when residual uptake by Ga-S after the first treatment for PCP was not detected. It may also be possible to start cART in the early phase after its treatment without the occurrence of PCP-IRIS with the appropriate additional treatment of PCP for 14 days. These guidelines for treatment of PCP in HIV-infected adults and adolescents have been recommended for the duration of 21 days since 1984. We propose that for the prevention of PCP-IRIS, it is nessecory to reconsider recommendation for the treatment duration of 21 days, and meanwhile to evaluate the treatment effect of PCP with Ga-S, because PCP resistance to sulfa drugs, namely are trimethoprim-sulfamethoxazole, is beginning to appear.

Virological characteristics of a SARS-CoV-2-related bat coronavirus, BANAL-20-236.

BACKGROUND: Although several SARS-CoV-2-related coronaviruses (SC2r-CoVs) were discovered in bats and pangolins, the differences in virological characteristics between SARS-CoV-2 and SC2r-CoVs remain poorly understood. Recently, BANAL-20-236 (B236) was isolated from a rectal swab of Malayan horseshoe bat and was found to lack a furin cleavage site (FCS) in the spike (S) protein. The comparison of its virological characteristics with FCS-deleted SARS-CoV-2 (SC2ΔFCS) has not been conducted yet. METHODS: We prepared human induced pluripotent stem cell (iPSC)-derived airway and lung epithelial cells and colon organoids as human organ-relevant models. B236, SARS-CoV-2, and artificially generated SC2ΔFCS were used for viral experiments. To investigate the pathogenicity of B236 in vivo, we conducted intranasal infection experiments in hamsters. FINDINGS: In human iPSC-derived airway epithelial cells, the growth of B236 was significantly lower than that of the SC2ΔFCS. A fusion assay showed that the B236 and SC2ΔFCS S proteins were less fusogenic than the SARS-CoV-2 S protein. The infection experiment in hamsters showed that B236 was less pathogenic than SARS-CoV-2 and even SC2ΔFCS. Interestingly, in human colon organoids, the growth of B236 was significantly greater than that of SARS-CoV-2. INTERPRETATION: Compared to SARS-CoV-2, we demonstrated that B236 exhibited a tropism toward intestinal cells rather than respiratory cells. Our results are consistent with a previous report showing that B236 is enterotropic in macaques. Altogether, our report strengthens the assumption that SC2r-CoVs in horseshoe bats replicate primarily in the intestinal tissues rather than respiratory tissues. FUNDING: This study was supported in part by AMED ASPIRE (JP23jf0126002, to Keita Matsuno, Kazuo Takayama, and Kei Sato); AMED SCARDA Japan Initiative for World-leading Vaccine Research and Development Centers "UTOPIA" (JP223fa627001, to Kei Sato), AMED SCARDA Program on R&D of new generation vaccine including new modality application (JP223fa727002, to Kei Sato); AMED SCARDA Hokkaido University Institute for Vaccine Research and Development (HU-IVReD) (JP223fa627005h0001, to Takasuke Fukuhara, and Keita Matsuno); AMED Research Program on Emerging and Re-emerging Infectious Diseases (JP21fk0108574, to Hesham Nasser; JP21fk0108493, to Takasuke Fukuhara; JP22fk0108617 to Takasuke Fukuhara; JP22fk0108146, to Kei Sato; JP21fk0108494 to G2P-Japan Consortium, Keita Matsuno, Shinya Tanaka, Terumasa Ikeda, Takasuke Fukuhara, and Kei Sato; JP21fk0108425, to Kazuo Takayama and Kei Sato; JP21fk0108432, to Kazuo Takayama, Takasuke Fukuhara and Kei Sato; JP22fk0108534, Terumasa Ikeda, and Kei Sato; JP22fk0108511, to Yuki Yamamoto, Terumasa Ikeda, Keita Matsuno, Shinya Tanaka, Kazuo Takayama, Takasuke Fukuhara, and Kei Sato; JP22fk0108506, to Kazuo Takayama and Kei Sato); AMED Research Program on HIV/AIDS (JP22fk0410055, to Terumasa Ikeda; and JP22fk0410039, to Kei Sato); AMED Japan Program for Infectious Diseases Research and Infrastructure (JP22wm0125008 to Keita Matsuno); AMED CREST (JP21gm1610005, to Kazuo Takayama; JP22gm1610008, to Takasuke Fukuhara; JST PRESTO (JPMJPR22R1, to Jumpei Ito); JST CREST (JPMJCR20H4, to Kei Sato); JSPS KAKENHI Fund for the Promotion of Joint International Research (International Leading Research) (JP23K20041, to G2P-Japan Consortium, Keita Matsuno, Takasuke Fukuhara and Kei Sato); JST SPRING (JPMJSP2108 to Shigeru Fujita); JSPS KAKENHI Grant-in-Aid for Scientific Research C (22K07103, to Terumasa Ikeda); JSPS KAKENHI Grant-in-Aid for Scientific Research B (21H02736, to Takasuke Fukuhara); JSPS KAKENHI Grant-in-Aid for Early-Career Scientists (22K16375, to Hesham Nasser; 20K15767, to Jumpei Ito); JSPS Core-to-Core Program (A. Advanced Research Networks) (JPJSCCA20190008, to Kei Sato); JSPS Research Fellow DC2 (22J11578, to Keiya Uriu); JSPS Research Fellow DC1 (23KJ0710, to Yusuke Kosugi); JSPS Leading Initiative for Excellent Young Researchers (LEADER) (to Terumasa Ikeda); World-leading Innovative and Smart Education (WISE) Program 1801 from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) (to Naganori Nao); Ministry of Health, Labour and Welfare (MHLW) under grant 23HA2010 (to Naganori Nao and Keita Matsuno); The Cooperative Research Program (Joint Usage/Research Center program) of Institute for Life and Medical Sciences, Kyoto University (to Kei Sato); International Joint Research Project of the Institute of Medical Science, the University of Tokyo (to Terumasa Ikeda and Takasuke Fukuhara); The Tokyo Biochemical Research Foundation (to Kei Sato); Takeda Science Foundation (to Terumasa Ikeda and Takasuke Fukuhara); Mochida Memorial Foundation for Medical and Pharmaceutical Research (to Terumasa Ikeda); The Naito Foundation (to Terumasa Ikeda); Hokuto Foundation for Bioscience (to Tomokazu Tamura); Hirose Foundation (to Tomokazu Tamura); and Mitsubishi Foundation (to Kei Sato).

Synthesis of dabsyl-appended cyclophanes and their heterodimer formation with pyrene-appended cyclophanes.

As a quencher-type host, dabsyl-appended cyclophanes bearing positively and negatively charged side chains (1a and 1b, respectively) were synthesized. Formation of cyclophane heterodimers of 1a with anionic fluorescent cyclophane bearing a pyrene moiety 2b was confirmed by fluorescence titration experiments. The 1:1 binding constant (K) of 1a toward 2b was calculated to be 1.6 × 10(5) M(-1). On the other hand, almost no complexation affinity of 1a toward cationic analogue of fluorescent cyclophane 2a was confirmed by the identical methods, indicating that electrostatic interactions became effective in the formation of cyclophane heterodimers. In addition, van't Hoff analysis applied to the temperature-dependent K values for the heterodimer formation gave negative enthalpy (ΔH) and entropy changes (ΔS). The large and negative ΔH values as well as small and also negative ΔS values showed that the complexation is an exothermic and enthalpy-controlled but not entropy-driven process. A similar trend of molecular recognition was also confirmed for formation of cyclophane heterodimers of 1b with 2a by the identical methods.

Inadequate structural constraint on Fab approach rather than paratope elicitation limits HIV-1 MPER vaccine utility.

Broadly neutralizing antibodies (bnAbs) against HIV-1 target conserved epitopes, thereby inhibiting viral entry. Yet surprisingly, those recognizing linear epitopes in the HIV-1 gp41 membrane proximal external region (MPER) are elicited neither by peptide nor protein scaffold vaccines. Here, we observe that while Abs generated by MPER/liposome vaccines may exhibit human bnAb-like paratopes, B-cell programming without constraints imposed by the gp160 ectodomain selects Abs unable to access the MPER within its native "crawlspace". During natural infection, the flexible hinge of IgG3 partially mitigates steric occlusion of less pliable IgG1 subclass Abs with identical MPER specificity, until affinity maturation refines entry mechanisms. The IgG3 subclass maintains B-cell competitiveness, exploiting bivalent ligation resulting from greater intramolecular Fab arm length, offsetting weak antibody affinity. These findings suggest future immunization strategies.

Inadequate structural constraint on Fab approach rather than paratope elicitation limits HIV-1 MPER vaccine utility.

Broadly neutralizing antibodies (bnAbs) against HIV-1 target conserved envelope (Env) epitopes to block viral replication. Here, using structural analyses, we provide evidence to explain why a vaccine targeting the membrane-proximal external region (MPER) of HIV-1 elicits antibodies with human bnAb-like paratopes paradoxically unable to bind HIV-1. Unlike in natural infection, vaccination with MPER/liposomes lacks a necessary structure-based constraint to select for antibodies with an adequate approach angle. Consequently, the resulting Abs cannot physically access the MPER crawlspace on the virion surface. By studying naturally arising Abs, we further reveal that flexibility of the human IgG3 hinge mitigates the epitope inaccessibility and additionally facilitates Env spike protein crosslinking. Our results suggest that generation of IgG3 subtype class-switched B cells is a strategy for anti-MPER bnAb induction. Moreover, the findings illustrate the need to incorporate topological features of the target epitope in immunogen design.

Resistance of SARS-CoV-2 variants to neutralization by antibodies induced in convalescent patients with COVID-19.

Administration of convalescent plasma or neutralizing monoclonal antibodies (mAbs) is a potent therapeutic option for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, SARS-CoV-2 variants with mutations in the spike protein have emerged in many countries. To evaluate the efficacy of neutralizing antibodies induced in convalescent patients against emerging variants, we isolate anti-spike mAbs from two convalescent COVID-19 patients infected with prototypic SARS-CoV-2 by single-cell sorting of immunoglobulin-G-positive (IgG+) memory B cells. Anti-spike antibody induction is robust in these patients, and five mAbs have potent neutralizing activities. The efficacy of most neutralizing mAbs and convalescent plasma samples is maintained against B.1.1.7 and mink cluster 5 variants but is significantly decreased against variants B.1.351 from South Africa and P.1 from Brazil. However, mAbs with a high affinity for the receptor-binding domain remain effective against these neutralization-resistant variants. Rapid spread of these variants significantly impacts antibody-based therapies and vaccine strategies against SARS-CoV-2.

Prediction of Contact Residues in Anti-HIV Neutralizing Antibody by Deep Learning.

The monoclonal antibody 1C10 targets the V3 loop of HIV-1 and neutralizes a broad range of clade B viruses. However, the mode of interaction between 1C10 and the V3 loop remains unclear because crystallization of 1C10 and the V3 peptide was unsuccessful due to the flexible regions present in both 1C10 and the V3 peptide. In this study, we predicted the 1C10 amino acid residues that make contact with the V3 loop using a deep learning (DL)-based method. Inputs from ROSIE for docking simulation and FastContact, Naccess, and PDBtools, to approximate interactions were processed by Chainer for DL, and outputs were obtained as probabilities of contact residues. Using this DL algorithm, D95, D97, P100a, and D100b of CDRH3; D53, and D56 of CDRH2; and D61 of FR3 were highly ranked as contact residues of 1C10. Substitution of these residues with alanine significantly decreased the affinity of 1C10 to the V3 peptide. Moreover, the higher the rank of the residue, the more the binding activity diminished. This study demonstrates that the prediction of contact residues using a DL-based approach is a precise and useful tool for the analysis of antibody-antigen interactions.

Clinical study of giant cell arteritis in our hospital.

OBJECTIVE: To investigate clinical and laboratory features of giant cell arteritis (GCA). METHOD: We included 24 patients (6 men, 18 women; mean age 69.8 years) in this study. GCA was diagnosed based on the American College of Rheumatology 1990 classification criteria. RESULTS: Mean serum C-reactive protein was 9.03 mg/dl. GCA was classified into three types: classic temporal arteritis type (cranial GCA, nine patients); large-vessel type, affecting the aorta and its major branches without temporal arteries (12 patients); generalized type, affecting both temporal arteries and large vessels (three patients). Swelling and tenderness of temporal arteries were recognized in temporal arteritis and generalized arteritis. Ten of these patients also had histopathologic findings of arteritis, including giant cells in biopsy specimens. Examination of HLA-class 1 expression showed that one patient with cranial GCA, three with generalized GCA, and seven with large-vessel GCA were positive for HLA-A24, and four patients with large-vessel GCA were positive for HLA-B39. One patient with cranial GCA, one with generalized GCA, and six with large-vessel GCA were positive for HLA-B52. Nine patients were positive for anti-phospholipid antibodies (seven for anti-cardiolipin antibody immunoglobulin G, seven for anti-cardiolipin ß2-glycoprotein-1 antibody, one for lupus anticoagulant). CONCLUSION: Our study demonstrated that HLA-class 1 expression in GCA resembles that in Takayasu arteritis, suggesting that these two arteritis types share the same genetic background. In contrast, the difference in the prevalence of anti-phospholipid antibodies in GCA and Takayasu arteritis patients shows a difference in the characteristic aspects of these two arteritis types.

Corticoid therapy for overlapping syndromes in an HIV-positive patient.

Human immunodeficiency virus (HIV) infection disturbs the host's immune function and often coexists with various autoimmune and/or systemic rheumatic diseases with manifestations that sometimes overlap with each other. We herein present the case of a 43-year-old Japanese man infected with HIV who exhibited elevated serum creatine kinase and transaminases levels without any symptoms. He was diagnosed with autoimmune hepatitis, polymyositis and Sjögren's syndrome and received combined antiretroviral therapy (cART); however, the laboratory abnormalities persisted. We successfully administered cART with the addition of oral prednisolone, and the patient's condition recovered without side effects related to the metabolic or immunosuppressive effects of these drugs.