The emergence of immunotherapies such as Immune checkpoint blockade (ICB), personalized tumor vaccines and oncolytic virus therapy is a milestone in the history of anti-tumor therapy. Unfortunately, immunotherapy is only effective for a limited number of cancer types and patients are likely to develop drug resistance in a short period of time. Recent studies have shown that in most solid cancers, high tumor mutation burden cannot serve as an accurate biomarker for predicting ICB responses. Therefore, a predictive biomarker for immunotherapy outcomes is needed. However, for immunotherapy how

We know very little about changing the immune microenvironment and how it works through tumor-non-tumor cell interactions. Tumor infiltrating lymphocytes (tils) are an important part of the tumor microenvironment (tme), affecting prognosis and clinical characteristics, and playing a fundamental role in tumor immunotherapy. Therefore, comprehensive and dynamic monitoring of tils can help further explore the boundaries of tumor immunotherapy.

Sequencing technology provides new insights into cell biology, disease pathogenesis and drug responses. Batch sequencing studies target the entire tumor to analyze the average gene expression of cells within the tumor. However, specific functional subpopulations that reflect the potential heterogeneity and plasticity of TME may be ignored. Tumors are composed mainly of tumor cells, stromal cells and immune cells, which can be divided into different subtypes. These cells constitute tumor heterogeneity and play a major role in tumor progression. The presence of scRNA-seq can explore tumor heterogeneity by analyzing and quantifying the entire transcriptome of a single cell. For a single cell, its genetics and epigenetics are revealed to predict its role in cancer and response to treatment. In addition, spatial transcription based on single cells reveals the local network of single cells’ spatial location and intercellular communication in the original tumor.

Recently, many cancer types of immune environments, such as melanoma, breast cancer, liver cancer, and non-small cell lung cancer, have been revealed by scRNA-seq, where T cells, B cells, bone marrow-derived inhibitor cells (MDSSCs), dendritic cells, and cytokines/chemokines they secrete form a complex interaction network. It is impressive that T cells have always been the main focus of research on anti-tumor functions, including Na?ve      T cells, effector memory T cells, and failure T

Cells, regulatory T cells and inhabited memory T cells, these are described in several cancers. B cells, as the main effector of humoral immunity, also play a significant role in TME components and immunotherapy responses. A large number of RNA sequencing shows that B cell-related markers have the greatest expression differences between immunotherapy responders and non-responders. B cells attack cancer in three ways: 1. Secretion of immunoglobulins mediates antibody-dependent cytotoxicity (), antibody-dependent cell phagocytosis ()

Adcp) and complement-dependent cytotoxicity (cdc); 2. Antigen presentation activates T cells; 3. Secretion of granzyme                                                                                                                                                                                                                                           �

Much more, this makes their complex mechanisms unclear in cancer immunotherapy. With the development of scRNA-seq technology, the location and function of til-bs can be accurately determined, which may help to better understand its mechanisms. From a single-cell perspective, in this paper, we discuss the til-bs subpopulation differentiation trajectory, interaction with other cells, and summarize the mechanisms of B cells to regulate time and affect immunotherapy effects, aiming to provide a new way for tumor research to target B cells.

Single-cell sequencing can further explore heterogeneity within the tumor. Unlike flow cytometry, mass spectrometry or any other previous methods, single-cell sequencing is a continuous method rather than a discrete method. The steps of scRNA-seq mainly include the following four steps: (1) single-cell isolation, (2) reverse transcription into cdna, (3) PCR amplification cdna, and (4) sequencing library construction (Figure 1a). Fluorescence-activated cell sorting (Facs) can be used to isolate specific cells from tissues (Figure 1a). In terms of b-cell research, flow cytometry is used to screen cd45 cells to increase the proportion of b-cells; targeting b-cells can also be directly selected based on the b-cell marker. As a sc

The breakthrough in RNA-seq technology, the microfluidic control system encapsulates a single cell in an independent micro droplet, which contains a unique molecular identifier (UMI) for barcoded microtranscriptional materials in single cells. According to the UMI of each cell, transcription information can be found in subsequent analysis even if the cells are lysed. Based on this feature, the 10×    genomics      chromium platform sequences thousands of cells at the same time. Compared with low-throughput methods such as smart-seq    2, 10×     genomics                                                                                                                                                                          �

In comparative studies of multiple scRNA-seq methods, 10×     genomics also have higher sensitivity, higher reads ratio matching mitochondrial genes, and lower noise than other high-throughput methods such as drop-seq and indrops [33]. Using the 10×     genomics and smart-seq2 platforms, subpopulations of B cells in CRC can be distinguished by different immunoglobulin heavy chain characteristics, and there is no obvious difference in clustering results. However, 10×    genomics also have shortcomings, it cannot cover all genes, and it has

3    'Regional bias, some important information may be missed when detecting gene mutations or MRNA splicing sites. In addition, this method has higher requirements for cell quality, and different tissues and different methods of obtaining samples are different. With scRNA-seq, we can more accurately define the subtypes of cells, track their developmental lineages, determine the relationship between cloning and phenotypes, map interactions and spatial relationships between different cells, thereby describing TME from multiple dimensions. In addition, a series of in vivo and in vitro experiments are needed to verify the results. We summarize the latest publications using scRNA-seq research

B-cell receptor (b         receptor,        bcr) is a membrane immunoglobulin that recognizes and binds specific antigens and plays an important role in the differentiation and maturation of B-cells. Bcr is composed of two heavy chains and two light chains, where the recombination of variable (v), diversity (d) and linking (j) gene sequences creates the diversity of B-cells. This complexity of this multi-gene makes it difficult to identify different receptors. However, because each B-cell is

Usually expressing a single receptor, potential antigen-specific receptors can be found through a given protocellular chain. The two main functions of bcr are as follows. First, it activates b cells by inducing parenchymal changes in the actin backbone and the expression of various genes during B cell activation. Second, it mediates the identification and extraction of antigens, resulting in the presence of processed peptides to T helper cells on the main histocompatibility complex ii                                                                                                                                                                                                      �

Further understanding of the trajectory of B-cell differentiation and its mechanism of specifically identifying antigens, especially when paired with the complete transcriptome identity of a single B-cell, this provides clues for understanding the development of cancer. More importantly, BCR sequencing can trace populations from single cells and reveal the relationship between cloning and phenotype. ScRNA-seq technology has natural advantages in BCR sequencing, because the microfluidic system containing UMI can ensure the preservation of homologous VH-VL pairings, which are these homologous VH

-VL pairing may be lost in B-cell batch sequencing. Basic is a platform for bcr sequencing at single-cell resolution. As a tool to reconstruct paired full-length bcr sequences, Bracer provides a complete pipeline for clonal inference and lineage tracing of B-cells. libra-seq is a high-throughput method that connects bcr      Se-sequences with their homologous antigen specificity and can be used to map antigen specificity of thousands of B-cells in a specific object.

Study immunoglobulins to explore the complexity of humoral immunity

Immunoglobulins are present in tumors and serum and play a dual role in tumors. Antibodies can crystallize (FC) through their fragments and are regulated by post-translational modification. Usually, immunoglobulins are secreted by plasma cells (PCS) of the bone marrow and spleen. PCs in tissue inflammation areas and inside tumors, especially in tertiary lymphoid structures (TLS), secrete tumor-related antibodies and directly induce in situ effects on the tumor. In terms of antitumor function, IGG is the most important class of human immunoglobulins because they can bind to the role of FCγ receptors on macrophages and natural killer cells, Adcp and CDC. In addition, IGG is crucial for antigen processing and presentation because antigens

The Fcγ receptor on presenting cells (APCSs) can bind to IGG-coated immune complexes to activate T cells. Single-cell sequencing of antibodies and antibody-secreting cells (APCSs) helps to further clarify the complex network of B-cell humoral immunity. A single-cell droplet microfluidic sequencing scheme has been reported for antibodies specifically binding to target cells, which is also suitable for primary human PC. Celligo is a droplet microfluidic system for high-throughput single-cell screening of primary cells secreting IGG. On the one hand, the IGG activity is detected by fluorescence-based single-cell in-droplet single-cell bioassay, and on the other hand, the paired V genes are sequenced using barcoded reverse transcription.

Immature B cells in peripheral blood enter B lymphatic follicles through high endothelial veins. In B cell follicles, Na?ve    B cells (cd27) contact the antigen through inherent ACP (including DCS and follicular dendritic cells (fdCS)), and then activate BCR signal to induce antigen extraction, internalization and processing, presenting the peptide on MHC     Ii. Then, B cells migrate to the edge of the follicle region adjacent to T cells, presenting the antigen to follicular assisted T      (tfh) cells. Therefore, TFH cells stimulate BCR and induce Na?ve    B cells differentiate, mainly including memory B

Cells (mbcs), short-lived B cells (short   -     lived                                                                                                                                                                                                                                            �

Hypermutation,     shm) changes, called affinity maturation. Next, they undergo a competitive process in the bright zone (LZ), where many B cells gather, their fate depends on their interaction with TFH cells, and may have the ability to capture and present antigens and undergo class-switching recombination (CSR). This process also relies on the results of TFH cell differentiation, resulting in the results of B cells. Low-affinity B cells become long-lived mbcs, high-affinity B cells become PCS, and other cells apoptotic or reenter the ****z for shm and clonal expansion. Recently

Studies have shown that Cmyc    lz    B cell subpopulation includes PC precursors with higher affinity or future DZ entrants, as well as some MBC precursors with lower affinity. It is worth noting that BCR plays a major role in this process. Two important checkpoints in the humoral immunity process of B cell differentiation are antigen presentation on Na?ve   B cells and GC     B cells, which may improve humoral immune response. In addition, complete transcriptome characterization at the single-cell level will be particularly helpful in determining the transcriptional trajectory and heterogeneity of Na?ve   B cells to PC differentiation.

B cells are unevenly distributed

Previous research on B cells was mainly based on immunohistochemistry or flow cytometry, which limited the clear classification of B cells. Wouters et al. reviewed 69 studies to study the prognostic significance of tilb in 19 cancers to explore the uncertainty of B cells' contribution to anti-tumor immunity, among which the prognostic significance of B cells is different. Studies have found that B cells activate the Fcrγ receptor on myeloid cells and promote the cancer of squamous cells. However, B cells with anti-cd20 antibodies promote the occurrence of melanoma in mice. So far, the function of B cells in tumors is not clear. This is mainly due to the fact that

There are different subpopulations of B cell in the same tissue, in terms of classification, function and space. The application of scRNA-seq provides high resolution, which can reveal uncertainty and inhomogeneity between different tissues, thereby revealing immunogenic or immunosuppressive TMEs. Usually, B cells only account for a small part of normal human organ cells. For example, B cells are limited (<1%) in normal pancreatic tissue, but account for about 5% in pancreatic cancer. In primary lung tumors, B cells are also more than normal lung tissue. In addition, the infiltration of normal lung tissue is mostly cell toxicity that secretes granzyme    b

B cells, while in primary lung tumors and lymph node metastasis, GC     B cells of different BCRs are increased due to clonal expansion and generation of tumor antigens. Similarly, compared with normal breast tissue, the density of til-bs increases in primary breast cancer. In addition, in breast cancer, til-bs express more th1 effector cytokines (ifng and tnfa) than B cells in secondary lymphoid tissue, suggesting type 1 cell immune response. In a triple-negative breast cancer (tnbc) cohort, scRNA-seq evidence shows that B cells in TME have more shm and CS

R is characterized by MBCS, while PBMCS is rich in more Na?ve    B cells. This may be because when primary tumor occurs, a large number of Na?ve    B cells in peripheral blood are stimulated by high-quality tumor neoantigens, and shm occurs in GCS, thus migrating to TME or TLS. However, through SCRNA-Seq analysis, compared with the pericarcinoma and precancerous tissues, human CRC tissue has higher proliferation status and higher dispersion, MHC                                                                                                                                                                                         �
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