General and Innate Immunity

General Immunity

• Immunity provides protection against disease that is generally infectious

Immune Response

• An immune response occurs when the body recognizes and defends itself again bacterias, viruses and substances that appear foreign and unsafe

Innate Immunity

• Innate immunity consists of defenses present before microorganism exposure
• Innate immunity natural barriers guard against infectious substances

Main components of Innate Immunity

• Keratin on intact skin acts as mechanical barrier
• Lysozyme in tears and secretions breaks down peptidoglycan
• Respiratory cilia elevate mucus, trapping microorganisms
• The pH in the stomach and vagina is acidic, slowing growth
• Surface phagocytes ingest and kill microorganisms
• Defensins create pores in microbial membranes
• Common flora occupies receptors, preventing colonisation

Factors Restgricting Growth

• Natural killer cells destroy virus infected cells
• Neutrophils ingest and destroy microorganisms
• Macrophages and dendtric cells ingest and kill microorganisms and present antigens
• Interferons inhibit replication
• The complement C3b opsonin and MAC creates holes
• Transferrin and lactoferrin sequester iron
• High Temperatures slow growth
• Inflammation inhibits dissemination

Acquired Immunity

• Acquired immunity occurs after agent exposure and improves with successive exposure
• Antibodies and Lymphocytes T mediate acquired immunity

Active and Passive Immunity

• Active immunity is induced after contact with foreign Ag; contact may come from clinical infections, immunisations with live agents or microbial products
• Hosts induce immune responses which include antibodies and cytotoxic T lymphocytes
• The main advantage is conferring long term resistance for pathogens, while the main disadvantage is slow progression
• Passive immunity confers resistance via existing antibodies found in another host
• Injection of antibiodies can treat rabies, hepatitis B, C
• IgG is transferred during pregnancy and lactation
• Rapid availability of large quantities of antibodies is the main benefit
• The disadvantage is the short life of antibodies and hypersensitivity if heterogenous globulines/proteins are used

Types of responses

• Humoral immunity involves blood molecules known as type B antibodies
• Humoral immunity defends against extracellula microbes and secreted toxins
• Cellular immunity involves lymphocytes T
• Cellular immunity defends the destruction of intracellular microorganisms in phagocytes or infected cells

Characteristics

• Specificity
• Diversity
• Memory
• Specialization
• Self-limitation
• Absence of autoimmunity

Lymphoid Organs

• Organs involved in the immune system

Generating Organs

• Lymphoid organs, provide environment to develop lymphocytes
• They ensure autotolerance by eliminating lymphocytes that attack the body's own autoantigens causing autoimmune

Bone Marrow

• Distributed in bones, especially long and spongy ones
• The bone marrow in mammals forms blood cells like lymphocytes
• The red bone marrow contains spongy tissue in flat bones like the sternum and ribs
• Yellow bone marrow: adipose tissue in the medullar channels of long bones

Thymus Gland

• The thymus is a gland that has central controls for immunity system
• It has two lobes behind the sternum
• A fully thymus develops in the third month of gestation, with a mass of 12–15 g. It continues growing to puberty, where it reaches a max of 30-40 grams
• In adulthood from 10 to 15g, replaced by adipose tissue

Peripheral Organs

• Peripheral organs allow naive lymphocytes to interact with Ag exogenously
• Peripheral organs promote interactions with the APC and antigen for lymphocytes
• Peripheral organs spread and stimulate immunity cells over the body

Lymphatic Ganglia

• In lymphatic ganglia, adaptive immune responses begin
• Immune cells are transported by lymph
• Ganglia groups have sites estrategically situated like:
  • Neck
  • Armpits
  • Groin
  • Abdominal cavity

Lymph Node Histology

• Cortex with B cells and macrophages
• Primary follicles rich in limphocites
• Secondary follicles form after antigenic stimulation
• Paracortex
• T cells and dendritic
• Medulla
  • Thymus independent antigens

Spleen

• Abdominal tissue, red, with functions in blood and immunity system
• Spleen in humans can measure 11cm long and 5cm wide
• The spleen processes red and white pulp
• Pulp clears foreign matter from the blood
• Pult generates immune responses, produces antibodies

Spleen Funcion

• Hematopoiesis During gestation makes blood but in adults only when needed
• Filter Destroy old abnormal red cells Immunity

MALT means Mucosa-Associated Lymphoid Tissue

Components

• Vascularised conective tissue The tissue that provdes support to conective tissue serves recruit limphotic area
• Parenquimotoic cells Parenquimotoic cells are cells that have capacity of celular tissue

Tertiary Lymphoid Tissue

• A group of tissues that has the function of capturing antigens

Lymphoid cells: Lymphocytes properties

• Lymphocytes can recognize
• Lymphocytes can differentiate
• Lymphocytes make the immune system active and is specific

Lymphocytes types and funcion

• B Limphocyto produce antibodies Activated with macrofagos by cytoquines secreters and stimulate cellular immunity

• T Limphocyes colavorators have stimulis for growth and differentiate, and immunity humoral

• T Limphocyto destroy cells infection for virus (Tumors) and cellulary immunity

• Celullas Citocida destroys virus and tumors

• Virus stimulates limphoctos in the bloodstream, 8-10 µm

• Virus stimulate tamaño 10 12 µm that have mayor cytoplasm

• Prolifera and difference life short; effecto life short

• Celulas de memoria and life longer

Myeloid Cells properties

• Polimofonucleares neutrofilo tiene nucles multilobulado.

• Presents granulos cytoplasm pink

• Granulos actio of bactericida

• Macrophagos that are mononuclear have a form of horseshoe

• It has 3 principal purposes of cytocines and fagocitosis

Location of macrofagos

• Alveolo in the pulmón

• Histicitos in conjunctival system

• Kupfer have liver

• Mesangles renion

• Microguiales cerebro

• Osteoblastio

• Have great quantity of mitochondrias, long duration

Basofilo mastecitos

• Have blue, they are in the sistematory resistatory
• Masticitos bajo la piel, respirator and intestin
• Hipersensibilidad alericas, la principal celulas que efecta es mastocitos
• It has a important function of capturar

Dendrític cells properties

• Are cells that have a great function of capturar and trasnportar with linfatic drain

• Dendriculas foliculares son area secudaria

• Dentrítical foliculares are areas that secondary that are in cells B of ganlios

• Células denteitas a essential paper of memory

• Increase in hypersensibilidad and can migrate in tejidos

• Tiene papel de fagocititos

• Defensa inespecífica parasitic