امين يا رب الله يسمع منك ابو علي

Class switching occurs after activation of a mature B cell via its membrane-bound antibody molecule (or B cell receptor) to generate the different classes of antibody, all with the same variable domains as the original antibody generated in the immature B cell during the process of V(D)J recombination, but possessing distinct constant domains in their heavy chains. Naïve mature B cells produce both IgM and IgD, which are the first two heavy chain segments in the immunoglobulin locus. After activation by antigen, these B cells proliferate. If these activated B cells encounter specific signaling molecules via their CD40 and cytokine receptors (both modulated by T helper cells), they undergo antibody class switching to produce IgG, IgA or IgE antibodies. During class switching, the constant region of the immunoglobulin heavy chain changes but the variable regions, and therefore antigenic specificity, stay the same. This allows different daughter cells from the same activated B cell to produce antibodies of different isotypes or subtypes (e.g. IgG1, IgG2 etc.) Class switching occurs by a mechanism called class switch recombination (CSR) binding. Class switch recombination is a biological mechanism that allows the class of antibody produced by an activated B cell to change during a process known as isotype or class switching. During CSR, portions of the antibody heavy chain locus are removed from the chromosome, and the gene segments surrounding the deleted portion are rejoined to retain a functional antibody gene that produces antibody of a different isotype. Double-stranded breaks are generated in DNA at conserved nucleotide motifs, called switch (S) regions, which are upstream from gene segments that encode the constant regions of antibody heavy chains; these occur adjacent to all heavy chain constant region genes with the exception of the δ-chain. DNA is nicked and broken at two selected S-regions by the activity of a series of enzymes, including Activation-Induced (Cytidine) Deaminase (AID), uracil DNA glycosylase and apyrimidic/apurinic (AP)-endonucleases.The intervening DNA between the S-regions is subsequently deleted from the chromosome, removing unwanted μ or δ heavy chain constant region exons and allowing substitution of a γ, α or ε constant region gene segment. The free ends of the DNA are rejoined by a process called non-homologous end joining (NHEJ) to link the variable domain exon to the desired downstream constant domain exon of the antibody heavy chain. In the absence of non-homologous end joining, free ends of DNA may be rejoined by an alternative pathway biased toward microhomology joins With the exception of the μ and δ genes, only one antibody class is expressed by a B cell at any point in time. While class switch recombination is mostly a deletional process, rearranging a chromosome in "cis", it can also occur (in 10 to 20% of cases, depending upon the Ig class) as an inter-chromosomal translocation mixing immunoglobulin heavy chain genes from both alleles. Good read: www.ncbi.nlm.nih.gov/pmc/articles/PMC2707252/

Good read: www.ncbi.nlm.nih.gov/pmc/articles/PMC6483358/

Good read: onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0897.1988.tb00205.x

Good read: www.ncbi.nlm.nih.gov/pmc/articles/PMC1538401/

Fantastic Voyage

Good read: www.sciencedirect.com/topics/medicine-and-dentistry/sperm-antigen

Monoclonal antibodies are secreted from only one specific clone of cells. Polyclonal antibodies are secreted by different cells within the body. They are a collection of immunoglobulin molecules that react against a specific antigen, each identifying a different epitope.

+samah sss صح

Dr. Mohamed Sherif Lectures طيب والclonal expansion كيف والinnate immunity صح انت حكيتلنا no I.R حطيتها هيك بالامتحان كتبلي الدكتور غلط كيف اقنته انو هيه صح ؟؟

Dr. Mohamed Sherif Lectures وشكرررااا كتيير لانك بترد عليه بسلمووو ويعطيك الصحة ياارب ويجعلك بالفردوس الاعلى

نوع خاص من الجزئيات البروتينية ينتج في المختبر. هنالك أنواع من المضاد الوحيد النسيلة، تنتجها ـ بصورة طبيعية ـ أجهزة المناعة في الإنسان والحيوان، عندما تهاجم المواد الخارجية (مثل البكتيريا والفيروسات) الجسم. وتستطيع الأجسام المضادة في الدم إبطال مفعول هذه المواد بالالتصاق بمستضداتها. والأجسام المضادة الطبيعية في الدم خليط من عدة أجسام مضادة، تتفاعل مع كثير من المستضدات؛ وبالتالي تعمل بمثابة خط دفاع أمامي للجسم ضد المرض. أما محلول المضاد الوحيد النسيلة فيعمل ضد مستضد معين، ويمكن أن يصنع بكميات كبيرة، يبشر بالنجاح في مجال البحوث الطبية.

@@DrMohamedSherifLectures شكرا جزيلا دكتورنا الطيب

Good read: www.ncbi.nlm.nih.gov/pubmed/1379277

ممنونه من حضرتك دكتور

Fantastic Voyage (1966)

Fantastic voyage

Fantastic voyage

Polyclonal antibodies (pAbs) are mixture of heterogeneous which are usually produced by different B cell clones in the body. They can recognize and bind to many different epitopes of a single antigen. Polyclonal antibodies are produced by injecting an immunogen into an animal. After being injected with a specific antigen to elicit a primary immune response, the animal is given a secondary even tertiary immunization to produce higher titers of antibodies against the particular antigen. After immunization, polyclonal antibodies can be obtained straight from the serum (blood which has had clotting proteins and red blood cells removed) or purified to obtain a solution which is free from other serum proteins. Monoclonal antibodies (mAbs) are generated by identical B cells which are clones from a single parent cell. This means that the monoclonal antibodies have monovalent affinity and only recognize the same epitope of an antigen. Unlike polyclonal antibodies, which are produced in live animals, monoclonal antibodies are produced ex vivo using tissue-culture techniques. The process begins with an injection of the desired antigen into an animal, often a mouse, multiple times. Once the animal develops an immune response, the B-lymphocytes are isolated from the animal’s spleen and fused with a myeloma cell line, creating immortalized B cell-myeloma hybridomas. The hybridomas, which are able to grow continuously in culture while producing antibodies, are then screened for desired mAb.

وانا صابني فضول ابغى اشوف الفلم🙄

ما عاد ركزت ع باقي المحاضرة و انا افكر بالفلم 😂😂😅

Humoral mainly