CN-121975006-A - Novel fully human antibody and application thereof

Abstract

The invention provides a novel fully human antibody and application thereof, and particularly provides a fully human antibody QC54 for resisting yellow fever virus. The heavy chain variable region and the light chain variable region of the humanized antibody respectively have the amino acid sequences shown in SEQ ID NO.1 and SEQ ID NO. 2. The affinity analysis shows that the antibody has good affinity, and cell experiments prove that the antibody has excellent antiviral capability and excellent prevention or treatment effect on yellow fever viruses, and has wide clinical application prospect.

Inventors

• HU SHI
• LEI CHANGHAI

Assignees

• 中国人民解放军海军军医大学

Dates

Publication Date

20260505

Application Date

20251218

Claims (7)

1. 1. The fully human antibody QC54 for resisting yellow fever virus is characterized in that the amino acid sequence of the heavy chain variable region is shown as SEQ ID NO.1, and the amino acid sequence of the light chain variable region is shown as SEQ ID NO. 2.
2. 2. A nucleic acid encoding the anti-yellow fever virus fully human antibody QC54 of claim 1.
3. 3. The method for preparing the anti-yellow fever virus fully human antibody QC54 according to claim 1, which comprises the following steps: (A) Synthesizing the whole length of the humanized antibody according to the whole gene of the antibody variable region gene; (B) Cloning the full-length humanized antibody obtained in the step (A) to an expression vector by adopting a PCR technology, and confirming that correct cloning is obtained after sequencing verification; (C) The expression vector is introduced into a host cell to express the fusion protein.
4. 4. A method for preparing anti-yellow fever virus fully human antibody QC54 as claimed in claim 3, wherein: Wherein the expression vector is pGEM-T, pet a, pcDNA3.1, pEE6.4, pEE12.4, pDHFR or pDR1, the expression vector comprises a fusion DNA sequence connected with proper transcription and translation regulatory sequences, The host cell is a prokaryotic cell, a mammalian cell, an insect cell, or a fungal cell.
5. 5. A pharmaceutical composition comprising the anti-yellow fever virus fully human antibody QC54 of any one of claims 1-2, further comprising a pharmaceutically acceptable pharmaceutical carrier.
6. 6. The pharmaceutical composition according to claim 5, wherein: wherein the pharmaceutical composition is a water injection or a freeze-dried preparation, The pharmaceutically acceptable drug carrier comprises one or a combination of a surfactant, a solution stabilizer, an isotonicity adjusting agent and a buffer.
7. 7. The use of the fully human antibody QC54 against yellow fever virus according to any one of claims 1-2 in the preparation of a medicament against yellow fever virus.

Description

Novel fully human antibody and application thereof Technical Field The invention belongs to the technical field of biological medicines, and particularly relates to a fully human antibody QC54 for resisting yellow fever virus, a preparation method thereof and application thereof in an antiviral infection preparation. Background Yellow fever virus (Yellow Fever Virus, YFV) is a mosquito-borne acute hemorrhagic fever virus belonging to the Flaviviridae family (flavoviridae) and is responsible for periodic outbreaks in africa and south america with high severe mortality. For the prevention and treatment of yellow fever, the vaccine popularization and mosquito prevention are mainly relied on, and life-long immunity can be provided after single inoculation. Although classical 17D attenuated vaccines have been used for nearly a hundred years and maintain a high degree of protective efficacy, global vaccine coverage is highly imbalanced, the vaccine supply chain is long-term inadequate, and immune persistence varies significantly among immunosuppressed people, infants, pregnant women, and the elderly. As international travel increases, the risk of case input increases, along with warming of the climate, causing the vector mosquito to spread, exacerbating the risk of YFV global spillover (spillover). Therefore, the development of broad-spectrum, strongly neutralizing, industrially producible monoclonal antibodies that can be used for post-exposure intervention (post-exposure prophylaxis), outbreak emergency reserves (outbreak stockpile), and special crowd protection has urgent public health value. However, antibody development of yellow fever virus is particularly challenging compared to dengue, zika, japanese encephalitis and other flaviviruses. First, the envelope protein E (envelope protein) of YFV has a high conformational plasticity, which is continuously and dynamically switched between mature virus, respiratory state (viral break), sub-mature virus, and post-fusion trimer. The structural differences between the different conformations significantly affect the extent of exposure of the critical epitope (epi) so that many potential neutralization sites can be captured by the antibody only in transient states of the viral lifecycle, thereby greatly increasing the difficulty of obtaining highly efficient antibodies. Second, the prM protein of these particles is not completely excised and tightly covers critical areas of the E protein surface, resulting in so-called prM occlusion (PRM SHIELDING), which is often produced in large amounts during YFV infection (immature/PARTIALLY MATURE PARTICLES). Of the antibodies induced either after natural infection or after 17D vaccination, there are a significant proportion of the antibodies that target immunodominant but non-functional regions on the prM-E complex, such as Fusion Loop (FL). Such antibodies, although strong in binding, are structurally limited in their ability to neutralize due to the lack of stereo chimeric features and may mediate ADE risk in the presence of sub-mature viruses, further narrowing the space available for antibodies. Third, the immunodominant pattern of YFV itself also constitutes a natural obstacle. Natural immunity strongly favors planar epitopes with poor structure (structurally feature-pore) such as FL, prM contact interfaces, and weak response to truly protective, trans-conformational conserved neutralization "supersite". This represents a great difficulty in obtaining high affinity, high neutralizing candidate antibodies in traditional immunized animal or human libraries, and must rely on design strategies of deep screening, single cell cloning, or strong structural driving. Fourth, high resolution cryo-EM data for YFV has not been perfected until recently, although there has been much structural study in the field of flaviviruses. In particular, the structural systems related to pre-fusion E dimer, post-fusion E trimer, prM-E complex, which have long been lacking in the past, have resulted in difficulties for researchers to ascertain which epitopes are stably exposed, which are highly overlapping in different conformations, and which can produce blocking effects at key steps in the viral lifecycle. This lag in structural information directly limits rational design implementation and also makes most antibodies screened previously limited in potency and unclear in mechanism. In addition, truly strong neutralizing antibodies often need to be provided with a "double-lock mechanism" at the same time: (1) Blocking viral adsorption, conformational transition or dimer rearrangement early in entry; (2) The E trimer is locked during the membrane fusion phase, preventing release of viral nucleic acid. However, it is extremely rare that antibodies capable of recognizing the same supersite continuously across both pre-fusion and post-fusion conformations, which have extremely high requirements on the recognition angle, affinity, interface depth and